2d:null 2e:["$","title",null,{"children":"Local Change History | Tom Larkworthy | Observable"}] 33:T488,md`## Isomorphic Git Changes are saved to a IndexDB filesystem (lightning-fs) in a git repository (ismorphic-git). Layout - one IndexDB filesystem (lopecode_history) - one repository per _notebook_ - one branch per host \`url\` (e.g. a blob:// in the case of tab forks) - one subdirectory per module - one file per variable, contents is the \`_definition\` So, everytime you fork a notebook into a new tab, you create a new host url (branch) and a new history branch. ~~~ lopecode-js - repo: notebook1 branch: blob://984i4opipoi dir: /modules/ - .js: (cell definition) - .json (cell metadata: name and inputs) ~~~ Git is quite slow to lookup file changes within a commit, so each commit message contains a JSON structured summary of what changed which can be parsed much quicker than accessing the object store. ### Stateless Git We avoid "checkouts" and other staging concepts because the filesystem is shared across tabs and can therefore clash. Two tabs will work on different branches, but they share a IndexDB filesystem, therefore each other's histories are visible. `34:T502,relevant_git_commits = { const commits = Array.isArray(git_commits) ? git_commits : []; const seen = new Set(); const keptNewestFirst = []; const coercePaths = summary => { const out = []; const push = v => { if (v == null) return; if (Array.isArray(v)) for (const x of v) push(x); else if (typeof v === 'string') out.push(v); }; if (Array.isArray(summary)) { push(summary); return out; } if (summary && typeof summary === 'object') { push(summary.new); push(summary.upd); push(summary.del); return out; } if (typeof summary === 'string') { try { return coercePaths(JSON.parse(summary)); } catch { return out; } } return out; }; for (const h of commits) { const paths = coercePaths(h?.summary ?? h?.commit?.message).filter(p => typeof p === 'string'); if (paths.length === 0) continue; let useful = false; for (const p of paths) { if (!seen.has(p)) { useful = true; break; } } if (!useful) continue; keptNewestFirst.push({ ...h, _paths: paths }); for (const p of paths) seen.add(p); } return keptNewestFirst; }35:T610,parseGitMessage = function parseGitMessage(message) { let payload = message; if (typeof payload === 'string') payload = JSON.parse(payload); const parseGitPath = path => { if (typeof path !== 'string') throw new Error('parseGitMessage: path must be a string'); const normalized = path.startsWith('/') ? path : `/${ path }`; const parts = normalized.split('/').filter(Boolean); if (parts.length < 4) throw new Error(`parseGitMessage: path too short to contain notebook/module/pid: ${ path }`); const notebook = `/${ parts[0] }/${ parts[1] }`; const filename = parts[parts.length - 1]; const module = parts.slice(2, -1).join('/'); const m = filename.match(/^(.*?)(?:\.([^.]+))?$/); const pid = m?.[1] ?? filename; const ext = m?.[2] ?? ''; return { path, notebook, module, pid, ext, filename }; }; if (Array.isArray(payload)) { return payload.map(p => ({ ...parseGitPath(p), op: 'upd' })); } if (payload && typeof payload === 'object') { const out = []; const pushAll = (op, arr) => { if (arr == null) return; const list = Array.isArray(arr) ? arr : [arr]; for (const p of list) out.push({ ...parseGitPath(p), op }); }; pushAll('new', payload.new); pushAll('upd', payload.upd); pushAll('del', payload.del); return out; } throw new Error('parseGitMessage: unsupported commit message shape (expected array or {new,upd,del})'); }36:Tbdb,GitEntry = class GitEntry { constructor({repo, branch, oid, pid, module, notebook, op = 'upd', source = 'git', t = null} = {}) { if (!repo) throw new Error('GitEntry: repo is required'); if (!branch) throw new Error('GitEntry: branch is required'); if (!oid) throw new Error('GitEntry: oid is required'); if (!pid) throw new Error('GitEntry: pid is required'); if (!module) throw new Error('GitEntry: module is required'); this.repo = repo; this.branch = branch; this.oid = oid; this.pid = pid; this.module = module; this.notebook = notebook; this.op = op; this.source = source; this.t = t; this.__loaded = null; this.__loadPromise = null; } async __readTextAtCommit(filepath) { await ensure_repo({ repo: this.repo }); try { const {object} = await git.readObject({ fs, dir: this.repo, oid: this.oid, filepath }); if (typeof object === 'string') return object; if (object == null) return ''; if (object instanceof Uint8Array) return new TextDecoder('utf-8').decode(object); if (ArrayBuffer.isView(object)) return new TextDecoder('utf-8').decode(object); if (object instanceof ArrayBuffer) return new TextDecoder('utf-8').decode(new Uint8Array(object)); return String(object); } catch (err) { const msg = err?.message || ''; const code = err?.code || err?.name || ''; if (code === 'NotFoundError' || code === 'ResolveRefError' || msg.includes('ENOENT') || msg.includes('NotFoundError')) return ''; throw err; } } async __load() { const base = `${ this.module }/${ this.pid }`; const [jsSrc, jsonSrc] = await Promise.all([ this.__readTextAtCommit(`${ base }.js`), this.__readTextAtCommit(`${ base }.json`) ]); let meta = {}; try { meta = jsonSrc ? JSON.parse(jsonSrc) : {}; } catch { meta = {}; } return { _name: meta?.name ?? null, _inputs: Array.isArray(meta?.inputs) ? meta.inputs : [], _definition: jsSrc || '', _js: jsSrc, _json: jsonSrc }; } _ensureLoaded() { if (this.__loaded) return Promise.resolve(this.__loaded); if (!this.__loadPromise) this.__loadPromise = this.__load().then(d => this.__loaded = d); return this.__loadPromise; } get _name() { return this._ensureLoaded().then(d => d._name); } get _inputs() { return this._ensureLoaded().then(d => d._inputs); } get _definition() { return this._ensureLoaded().then(d => d._definition); } materialize() { return this._ensureLoaded().then(d => ({ source: this.source, op: this.op, t: this.t, pid: this.pid, module: this.module, notebook: this.notebook, oid: this.oid, repo: this.repo, branch: this.branch, _name: d._name, _inputs: d._inputs, _definition: d._definition })); } }37:T1065,replayGitEntries = async function replayGitEntries(gitEntries, { defaultModule = 'main' } = {}) { const entries = Array.isArray(gitEntries) ? gitEntries : []; const moduleByName = new Map(); if (modules instanceof Map) for (const [m, meta] of modules) if (meta?.name) moduleByName.set(meta.name, m); const defaultRuntimeModule = moduleByName.get(defaultModule) ?? moduleByName.get('main') ?? (modules instanceof Map ? modules.keys().next().value : null) ?? null; const ensureVariable = (pid, moduleName) => { const existing = getVariableByPersistentId(pid, runtime) ?? replay_pid_map.get(pid) ?? null; if (existing) return { variable: existing, created: false, module: null }; const mod = moduleByName.get(moduleName) ?? defaultRuntimeModule; if (!mod) return { variable: null, created: false, module: null, reason: 'module not found' }; const v = mod.variable(); replay_pid_map.set(pid, v); return { variable: v, created: true, module: mod }; }; const results = []; for (const e0 of entries) { const e = e0 instanceof GitEntry ? e0 : null; if (!e) { results.push({ ok: false, reason: 'not a GitEntry', entry: e0 }); continue; } const pid = e.pid ?? null; const op = e.op ?? 'upd'; const moduleName = e.module ?? defaultModule; if (!pid) { results.push({ ok: false, op, reason: 'missing pid', entry: e }); continue; } if (op === 'del') { const v = getVariableByPersistentId(pid, runtime) ?? replay_pid_map.get(pid) ?? null; if (v) { try { v.delete?.(); replay_pid_map.delete(pid); results.push({ ok: true, pid, op, action: 'delete', had: true }); } catch (err) { results.push({ ok: false, pid, op, action: 'delete', had: true, reason: String(err?.message ?? err) }); } } else { results.push({ ok: true, pid, op, action: 'delete', had: false }); } continue; } const { variable, created, reason: createReason } = ensureVariable(pid, moduleName); if (!variable) { results.push({ ok: false, pid, op, reason: createReason ?? 'could not create/locate variable', module: moduleName }); continue; } let mat; try { mat = await e.materialize(); } catch (err) { results.push({ ok: false, pid, op, reason: 'materialize failed: ' + String(err?.message ?? err), module: moduleName }); continue; } let defRaw = null; try { defRaw = (await realize([mat?._definition ?? ''], runtime))[0] ?? null; } catch { defRaw = null; } if (!defRaw) { results.push({ ok: false, pid, op, reason: 'could not realize definition', module: moduleName }); continue; } const prov = { source: e.source ?? 'git', repo: e.repo ?? null, branch: e.branch ?? null, oid: e.oid ?? null, t: e.t ?? mat?.t ?? Date.now(), pid }; const def = tag(defRaw, prov); const name = ((typeof mat?._name === 'string' && mat._name.length) ? mat._name : null) ?? pid; const inputs = Array.isArray(mat?._inputs) ? mat._inputs : []; try { variable.define(name, inputs, def); results.push({ ok: true, pid, op, action: 'define', name, inputs, module: moduleName, created }); } catch (err) { results.push({ ok: false, pid, op, action: 'define', name, inputs, module: moduleName, created, reason: String(err?.message ?? err) }); } } return results; }38:T712,replayGitCommits = async function replayGitCommits(commits, {repo = config?.repo, branch = config?.branch, order = 'oldest-first'} = {}) { const list = Array.isArray(commits) ? commits : []; const ordered = order === 'newest-first' ? list.slice() : order === 'oldest-first' ? list.slice().reverse() : list.slice(); const entries = []; const skippedModules = new Set(); for (const h of ordered) { const msg = h?.commit?.message ?? h?.summary ?? null; if (!msg) continue; let parsed; let rawPayload; try { rawPayload = typeof msg === 'string' ? JSON.parse(msg) : msg; parsed = parseGitMessage(msg); } catch { continue; } const baseHashes = rawPayload?.baseHashes ?? null; const byPid = new Map(); for (const p of parsed) if (p?.pid) byPid.set(p.pid, p); const tsSec = h?.commit?.committer?.timestamp ?? h?.commit?.author?.timestamp ?? null; const ts = tsSec == null ? null : tsSec * 1000; for (const p of byPid.values()) { const moduleName = p.module ?? 'main'; if (baseHashes && baseHashes[moduleName]) { const currentHash = moduleBaseHash(moduleName); if (!currentHash || currentHash !== baseHashes[moduleName]) { if (!skippedModules.has(moduleName)) { skippedModules.add(moduleName); console.log(`[local-change-history] Skipping replay for module "${ moduleName }" — base changed or module absent`); } continue; } } entries.push(new GitEntry({ source: 'git', op: p.op ?? 'upd', repo, branch, oid: h?.oid ?? 'HEAD', pid: p.pid, module: moduleName, notebook: p.notebook, t: ts })); } } return replayGitEntries(entries); }39:T54d,git_repo_layout = { const repo = config?.repo ?? null; if (!repo) return { ok: false, reason: 'missing config.repo' }; const stat = async path => { try { const s = await fs.stat(path); return { ok: true, type: s?.type ?? null, size: s?.size ?? null }; } catch (e) { return { ok: false, error: String(e?.message ?? e), code: e?.code ?? e?.name ?? null }; } }; const readText = async path => { try { const b = await fs.readFile(path); if (typeof b === 'string') return { ok: true, text: b }; if (b instanceof Uint8Array) return { ok: true, text: new TextDecoder('utf-8').decode(b) }; if (ArrayBuffer.isView(b)) return { ok: true, text: new TextDecoder('utf-8').decode(b) }; return { ok: true, text: String(b) }; } catch (e) { return { ok: false, error: String(e?.message ?? e), code: e?.code ?? e?.name ?? null }; } }; return { repo, nonbare: { head: await readText(`${ repo }/.git/HEAD`), objects: await stat(`${ repo }/.git/objects`), refs_heads: await stat(`${ repo }/.git/refs/heads`) } }; }3a:T5e0,setFilesAndCommit = async function setFilesAndCommit({repo, branch, data}) { await ensure_branch({ repo, branch }); let headOid = null; try { headOid = await git.resolveRef({ fs, dir: repo, ref: branch }); } catch { headOid = null; } const existsAtHead = async filepath => { if (!headOid) return false; try { await git.readObject({ fs, dir: repo, oid: headOid, filepath }); return true; } catch (err) { const msg = err?.message || ''; const code = err?.code || err?.name || ''; if (code === 'NotFoundError' || code === 'ResolveRefError' || msg.includes('ENOENT') || msg.includes('NotFoundError')) return false; return false; } }; const summary = { new: [], upd: [], del: [] }; let hasFiles = false; for (const [path, content] of data) { hasFiles = true; const full_path = `${ repo }/${ path }`; const lastSlash = full_path.lastIndexOf('/'); const dir = lastSlash === -1 ? repo : full_path.slice(0, lastSlash); await ensure_dir({ dir }); const isUpd = await existsAtHead(path); (isUpd ? summary.upd : summary.new).push(full_path); await fs.writeFile(full_path, content); await git.add({ fs, dir: repo, filepath: path }); } if (!hasFiles) return; await git.commit({ fs, dir: repo, author: { name: '-' }, message: JSON.stringify(summary) }); }3b:T523,listRepos = async function listRepos({root = '/', maxDepth = 4} = {}) { const norm = p => p === '/' ? '/' : p.replace(/\/+$/, ''); root = norm(root); const repos = new Set(); const visited = new Set(); const q = [{ path: root, depth: 0 }]; const safeReaddir = async p => { try { return await fs.readdir(p); } catch (e) { return null; } }; const safeStat = async p => { try { return await fs.stat(p); } catch (e) { return null; } }; while (q.length) { const {path, depth} = q.shift(); const key = `${ depth }:${ path }`; if (visited.has(key)) continue; visited.add(key); const stat = await safeStat(path); if (!stat || stat.type !== 'dir') continue; const names = await safeReaddir(path); if (!names) continue; if (names.includes('.git')) repos.add(path); if (depth >= maxDepth) continue; for (const name of names) { if (name === '.' || name === '..') continue; const child = path === '/' ? `/${ name }` : `${ path }/${ name }`; const cstat = await safeStat(child); if (cstat && cstat.type === 'dir') q.push({ path: child, depth: depth + 1 }); } } return Array.from(repos).sort(); }3c:T562,getCommitChanges = async function getCommitChanges({repo, oid} = {}) { if (!repo) throw new Error('repo is required'); if (!oid) throw new Error('oid is required'); const {commit} = await git.readCommit({ fs, dir: repo, oid }); const parentOid = commit.parent && commit.parent[0] ? commit.parent[0] : null; const filesAt = async ref => { if (!ref) return new Map(); const filepaths = await git.listFiles({ fs, dir: repo, ref }); const entries = await Promise.all(filepaths.map(async filepath => { const {oid: blobOid} = await git.readObject({ fs, dir: repo, oid: ref, filepath }); return [ filepath, blobOid ]; })); return new Map(entries); }; const [currFiles, parentFiles] = await Promise.all([ filesAt(oid), filesAt(parentOid) ]); const added = []; const modified = []; const removed = []; for (const [filepath, blobOid] of currFiles) { if (!parentFiles.has(filepath)) { added.push(filepath); } else if (parentFiles.get(filepath) !== blobOid) { modified.push(filepath); } } for (const filepath of parentFiles.keys()) { if (!currFiles.has(filepath)) { removed.push(filepath); } } return { oid, parentOid, added, modified, removed }; }3d:Ta2e,revertVariables = { return async entries => { const out = []; // For each selected change, restore its variable to the state it had // immediately BEFORE that change. Reconstructed from the history log + // initial_state, since entries carry no `previous` field. for (const e of entries ?? []) { const pid = e?.pid ?? null; if (!pid) continue; const variable = getVariableByPersistentId(pid, runtime) || null; if (!variable) { out.push({ pid, ok: false, reason: 'no runtime variable' }); continue; } // find the prior snapshot for this pid: the last same-pid entry before `e` const at = history.indexOf(e); const upTo = at === -1 ? history.length - 1 : at - 1; let prev = null, firstForPid = null; for (let idx = 0; idx <= upTo; idx++) { const h = history[idx]; if (h?.pid !== pid) continue; if (firstForPid === null) firstForPid = h; prev = h; } if (!prev) { // nothing earlier for this pid — either it existed before recording, // or this change first created it (op 'new') so reverting deletes it const base = initial_state instanceof Map ? initial_state.get(pid) ?? null : null; if (e?.op === 'new' || !base) { try { variable.delete?.(); out.push({ pid, ok: true, action: 'delete' }); } catch (err) { out.push({ pid, ok: false, action: 'delete', reason: String(err?.message ?? err) }); } continue; } prev = base; } const def = (await realize([prev._definition ?? ''], runtime))[0]; if (!def) { out.push({ pid, ok: false, reason: 'could not realize previous definition' }); continue; } const name = ((typeof prev._name === 'string' && prev._name.length) ? prev._name : null) ?? ((typeof variable._name === 'string' && variable._name.length) ? variable._name : null) ?? pid; try { variable.define(name, Array.isArray(prev._inputs) ? prev._inputs : [], def); out.push({ pid, ok: true, action: 'define' }); } catch (err) { out.push({ pid, ok: false, action: 'define', reason: String(err?.message ?? err) }); } } return out; }; }3e:Ta38,change_listener = { // scan the runtime for things that were loaded before we attached the hook if (!this) { const t = Date.now(); [...runtime._variables].forEach(variable => { viewof initial_state.value.set(persistentId(variable), historyUtils.snapshotVariable(variable)); viewof module_load_time.value.set(variable._module, t); }); } const inferProvenance = (v, previous) => { const currDef = v?._definition ?? null; const prevDef = previous?.variable?._definition ?? previous?._definition ?? null; return read(currDef) ?? read(prevDef) ?? null; }; const stop = onCodeChange(({variable, previous, t}) => { // playback drives defines/deletes; suppress recording while it runs if (playback_suspend && Date.now() < playback_suspend.until) return; let v = variable || previous.variable; // lazyImport // Suprised the do not referentially match if (v._definition.toString() === identity.toString()) return; if (typeof v?._name == 'string' && v._name.startsWith('dynamic ')) return; if (typeof previous?._name == 'string' && previous._name.startsWith('dynamic ')) return; const pid = persistentId(v); const module = v._module; const moduleName = modules.get(module)?.name || 'unknown'; const prov = inferProvenance(variable, previous); const source = prov?.source ?? 'runtime'; // playback replays existing history; never record it as a fresh change if (source === 'playback') return; if (variable && !previous) { // new variable // record it as a base state viewof initial_state.value.set(pid, historyUtils.snapshotVariable(variable)); if ((!viewof module_load_time.value.get(variable._module) || t < viewof module_load_time.value.get(variable._module) + 1000) && source == 'runtime') { // its a new module loading viewof module_load_time.value.set(module, t); return; } } if (variable) { // its a user defined variable historyUtils.insertByTime(viewof history.value, { t, op: previous ? 'upd' : 'new', source, pid, module: moduleName, provenance: prov, ...historyUtils.snapshotVariable(variable) }); } else { historyUtils.insertByTime(viewof history.value, { t, op: 'del', source, pid, module: moduleName, provenance: prov, _name: previous._name }); } viewof history.dispatchEvent(new Event('input')); }); invalidation.then(stop); return 'initialized'; }3f:T646,commitRuntimeHistorySince = async function commitRuntimeHistorySince({repo, branch, history, watermarkKey = `${ repo }:${ branch }`} = {}) { const prev = commit_watermarks.get(watermarkKey) ?? 0; const entries = Array.isArray(history) ? history : []; const allowedOps = new Set([ 'new', 'upd', 'del' ]); const pending = entries.filter(e => (e?.t ?? 0) > prev).filter(e => e?.source !== 'git').filter(e => allowedOps.has(e?.op)).sort((a, b) => (a?.t ?? 0) - (b?.t ?? 0)); let maxT = prev; const results = []; for (const change of pending) { try { const r = await commit_changes({ repo, branch, change }); results.push(r); if ((change?.t ?? 0) > maxT) maxT = change.t; } catch (err) { const failure = { ok: false, error: String(err?.message ?? err), change: { t: change?.t ?? null, op: change?.op ?? null, pid: change?.pid ?? null, module: change?.module ?? null, source: change?.source ?? null, _name: change?._name ?? null } }; results.push(failure); return { ok: false, watermarkKey, previous: prev, current: prev, attempted: pending.length, committed: results.filter(d => d?.ok).length, results }; } } commit_watermarks.set(watermarkKey, maxT); return { ok: true, watermarkKey, previous: prev, current: maxT, attempted: pending.length, committed: results.filter(d => d?.ok).length, results }; }40:T1c54,commit_changes = { return async ({repo, branch, change} = {}) => { if (!repo) throw new Error('commit_changes_direct: repo is required'); if (!branch) throw new Error('commit_changes_direct: branch is required'); if (!change) throw new Error('commit_changes_direct: change is required'); const pid0 = change?.pid; if (pid0 == null) throw new Error('commit_changes_direct: change.pid is required'); const pid = typeof pid0 === 'string' ? pid0 : String(pid0); const module_name = change?.module ?? 'main'; let op = change?.op ?? 'upd'; op = op === 'new' || op === 'upd' || op === 'del' ? op : 'upd'; await ensure_branch({ repo, branch }); const branchRef = `refs/heads/${ branch }`; const resolveHeadOid = async () => { try { return await git.resolveRef({ fs, dir: repo, ref: branchRef }); } catch { return null; } }; const readCommitTreeOid = async commitOid => { if (!commitOid) return null; const {commit} = await git.readCommit({ fs, dir: repo, oid: commitOid }); return commit?.tree ?? null; }; const readTreeCached = async (treeOid, cache) => { if (!treeOid) return []; if (cache.has(treeOid)) return cache.get(treeOid); const {tree} = await git.readTree({ fs, dir: repo, oid: treeOid }); cache.set(treeOid, tree); return tree; }; const existsAtTree = async (rootTreeOid, filepath, treeCache) => { if (!rootTreeOid) return false; const parts = String(filepath).split('/').filter(Boolean); let treeOid = rootTreeOid; for (let i = 0; i < parts.length; i++) { const seg = parts[i]; const entries = await readTreeCached(treeOid, treeCache); const ent = entries.find(e => e.path === seg); if (!ent) return false; if (i === parts.length - 1) return !!ent.oid; if (ent.type !== 'tree') return false; treeOid = ent.oid; } return false; }; const Node = () => ({ files: new Map(), dirs: new Map() }); const addUpdate = (node, segments, update) => { if (!segments.length) return; const [head, ...rest] = segments; if (!head) return; if (!rest.length) { node.files.set(head, update); return; } let child = node.dirs.get(head); if (!child) node.dirs.set(head, child = Node()); addUpdate(child, rest, update); }; const applyDir = async (treeOid, node, treeCache) => { const entries = new Map(); if (treeOid) { const tree = await readTreeCached(treeOid, treeCache); for (const e of tree) entries.set(e.path, { ...e }); } for (const [name, up] of node.files) { if (up?.op === 'del') { entries.delete(name); } else if (up?.op === 'put') { entries.set(name, { mode: up.mode ?? '100644', path: name, oid: up.oid, type: 'blob' }); } else { throw new Error(`commit_changes_direct: unknown file update op for ${ name }`); } } for (const [name, childNode] of node.dirs) { const existing = entries.get(name); const childTreeOid = existing && existing.type === 'tree' ? existing.oid : null; const newChildOid = await applyDir(childTreeOid, childNode, treeCache); if (!newChildOid) entries.delete(name); else entries.set(name, { mode: '040000', path: name, oid: newChildOid, type: 'tree' }); } if (entries.size === 0) return null; const tree = Array.from(entries.values()).map(e => ({ mode: e.mode, path: e.path, oid: e.oid, type: e.type })).sort((a, b) => a.path < b.path ? -1 : a.path > b.path ? 1 : 0); return git.writeTree({ fs, dir: repo, tree }); }; const headOid = await resolveHeadOid(); const headTreeOid = await readCommitTreeOid(headOid); const base = `${ module_name }/${ pid }`; const codePath = `${ base }.js`; const metaPath = `${ base }.json`; const fullCodePath = `${ repo }/${ codePath }`; const fullMetaPath = `${ repo }/${ metaPath }`; const root = Node(); if (op === 'del') { addUpdate(root, codePath.split('/').filter(Boolean), { op: 'del' }); addUpdate(root, metaPath.split('/').filter(Boolean), { op: 'del' }); } else { const enc = new TextEncoder(); const content = String(change?._definition ?? ''); const metadata = JSON.stringify({ name: change?._name ?? null, inputs: Array.isArray(change?._inputs) ? change._inputs : [] }); const [codeBlobOid, metaBlobOid] = await Promise.all([ git.writeBlob({ fs, dir: repo, blob: enc.encode(content) }), git.writeBlob({ fs, dir: repo, blob: enc.encode(metadata) }) ]); addUpdate(root, codePath.split('/').filter(Boolean), { op: 'put', oid: codeBlobOid, mode: '100644' }); addUpdate(root, metaPath.split('/').filter(Boolean), { op: 'put', oid: metaBlobOid, mode: '100644' }); } const treeCache = new Map(); let newRootTreeOid = await applyDir(headTreeOid, root, treeCache); if (!newRootTreeOid) newRootTreeOid = await git.writeTree({ fs, dir: repo, tree: [] }); const existedCode = await existsAtTree(headTreeOid, codePath, treeCache); const existedMeta = await existsAtTree(headTreeOid, metaPath, treeCache); const existedAny = existedCode || existedMeta; const summary = { new: [], upd: [], del: [] }; if (op === 'del') { if (existedCode) summary.del.push(fullCodePath); if (existedMeta) summary.del.push(fullMetaPath); } else { (existedAny ? summary.upd : summary.new).push(fullCodePath, fullMetaPath); } // Add base hash for the affected module const baseHash = moduleBaseHash(module_name); if (baseHash) { summary.baseHashes = { [module_name]: baseHash }; } const now = Date.now(); const author = { name: '-', email: '-', timestamp: Math.floor(now / 1000), timezoneOffset: new Date().getTimezoneOffset() }; const commit = { tree: newRootTreeOid, parent: headOid ? [headOid] : [], author, committer: author, message: JSON.stringify(summary) }; const newCommitOid = await git.writeCommit({ fs, dir: repo, commit }); await git.writeRef({ fs, dir: repo, ref: branchRef, value: newCommitOid, force: true }); return { ok: true, op, pid, module: module_name, headOid, newCommitOid, ref: branchRef, summary }; }; }41:T63e,viewof playback = { const n = history.length; const form = html``; let value = n, timer = null; const stop = () => { if (timer) { clearInterval(timer); timer = null; form.play.textContent = '\u25B6 play'; } }; const go = async v => { value = Math.max(0, Math.min(n, v | 0)); form.range.value = value; form.out.value = `${ value } / ${ n }`; form.value = value; await applyHistoryState(value); form.dispatchEvent(new Event('input', { bubbles: true })); }; form.range.oninput = () => go(+form.range.value); form.first.onclick = () => go(0); form.prev.onclick = () => go(value - 1); form.next.onclick = () => go(value + 1); form.last.onclick = () => go(n); form.play.onclick = () => { if (timer) return stop(); form.play.textContent = '\u23F8 pause'; timer = setInterval(() => go(value >= n ? 0 : value + 1), 700); }; invalidation.then(stop); form.value = value; return form; }42:T89d,applyHistoryState = { const moduleByName = new Map(); if (modules instanceof Map) for (const [m, meta] of modules) if (meta?.name) moduleByName.set(meta.name, m); const defaultMod = moduleByName.get('main') ?? (modules instanceof Map ? modules.keys().next().value : null) ?? null; // Reconstruct notebook state after the first `index` recorded changes, from the // history log + initial_state base snapshots. Entries carry no `previous` field, // so this also drives git-replayed history. return async function applyHistoryState(index) { // Suspend recording for the apply + a grace window: playback's redefines/deletes // fire onCodeChange asynchronously and must not be logged as fresh changes. playback_suspend.until = Date.now() + 4000; const i = Math.max(0, Math.min(index | 0, history.length)); const byPid = new Map(); history.forEach((h, idx) => { if (!h?.pid) return; let g = byPid.get(h.pid); if (!g) byPid.set(h.pid, g = { first: h, last: null }); if (idx < i) g.last = h; }); for (const [pid, {first, last}] of byPid) { const del = last ? last.op === 'del' : first.op === 'new'; const snap = del ? null : last ?? initial_state.get(pid) ?? null; let v = getVariableByPersistentId(pid, runtime) ?? replay_pid_map.get(pid) ?? null; if (del) { if (v) { try { v.delete?.(); } catch { } replay_pid_map.delete(pid); } continue; } if (!snap) continue; if (!v) { const mod = moduleByName.get((last ?? first)?.module ?? 'main') ?? defaultMod; if (!mod) continue; replay_pid_map.set(pid, v = mod.variable()); } let def = null; try { def = (await realize([snap._definition ?? ''], runtime))[0] ?? null; } catch { } if (!def) continue; v.define(snap._name || pid, Array.isArray(snap._inputs) ? snap._inputs : [], tag(def, { source: 'playback', pid })); } playback_suspend.until = Date.now() + 500; return i; }; }43:[] 31:{"id":"50857b98f55745c3","slug":"local-change-history","title":"Local Change History","thumbnail":"406a2263a52f2e046e812e82a41f96a908485b3ab3b277802a44041d6905e1de","access_level":"unlisted","create_time":"$D2025-12-01T20:27:13.163Z","update_time":"$D2026-07-12T15:20:35.128Z","view_time":null,"first_public_time":null,"has_unpublished_edits":null,"fork":{"id":"cf93635398c5c302","slug":"change-history","title":"Change History","owner":{"id":"7db5ed2b0697d645","login":"tomlarkworthy","name":"Tom Larkworthy"}},"stars":0,"starred":false,"owner":{"type":"team","id":"7db5ed2b0697d645","login":"tomlarkworthy","name":"Tom Larkworthy","avatar_url":"https://avatars-next.observableusercontent.com/47327a8bc1966f2186dcb3ebf4b7ee6e4e7ab9a5c2a07405aff57200ea778f71","tier":"starter_2024"},"version":2224,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"5215f6ec4a999d40","login":"tomlarkworthy","name":"Tom Larkworthy","avatar_url":"https://avatars-next.observableusercontent.com/47327a8bc1966f2186dcb3ebf4b7ee6e4e7ab9a5c2a07405aff57200ea778f71","tier":null}],"members":[{"type":"individual","id":"5215f6ec4a999d40","login":"tomlarkworthy","name":"Tom Larkworthy","avatar_url":"https://avatars-next.observableusercontent.com/47327a8bc1966f2186dcb3ebf4b7ee6e4e7ab9a5c2a07405aff57200ea778f71","tier":null,"role":"editor"},{"type":"team","id":"7db5ed2b0697d645","login":"tomlarkworthy","name":"Tom Larkworthy","avatar_url":"https://avatars-next.observableusercontent.com/47327a8bc1966f2186dcb3ebf4b7ee6e4e7ab9a5c2a07405aff57200ea778f71","tier":"starter_2024","role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"title":"Local Change History","cells":[{"id":2059,"value":"md`# Local Change History\n\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2060,"value":"viewof temporal = Inputs.select([\n 'temporal',\n 'discrete'\n], {\n label: 'y-axis',\n value: 'discrete'\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2061,"value":"viewof rewind = Plot.plot({\n marginLeft: 200,\n width,\n y: {\n type: temporal == 'temporal' ? 'time' : 'point',\n reverse: true,\n tickFormat: f => new Date(f)\n },\n marks: [\n ...history.length ? [Plot.ruleY([d3.max(history, d => d.t)], { stroke: 'green' })] : [],\n Plot.ruleX(history, {\n x: h => h.pid,\n strokeDasharray: [\n 1,\n 10\n ]\n }),\n Plot.dot(history, {\n x: h => h.pid,\n y: 't',\n symbol: 'op',\n stroke: h => h.pid,\n channels: {\n name: '_name',\n definition: '_definition'\n },\n tip: {\n format: {\n y: false,\n symbol: true,\n stroke: false,\n x: false,\n name: true\n }\n }\n }),\n Plot.ruleY(temporal == 'temporal' ? timeline : history.map(e => e.t), Plot.pointerY({ stroke: 'red' }))\n ]\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2062,"value":"viewof selectedChanges = Inputs.table(history, {\n columns: [\n 't',\n 'op',\n 'source',\n '_name',\n '_inputs',\n '_definition'\n ],\n format: {\n t: t => new Date(t).toISOString(),\n _definition: d => d.toString(),\n _inputs: i => html`

${ i.length }

${ i.map(i => html`${ i }
`) }`,\n source: s => ({\n runtime: '\\uD83D\\uDCD3',\n git: '\\uD83D\\uDCBE'\n }[s]),\n op: t => ({\n upd: '\\u270D️',\n del: '\\u2421',\n new: '\\uD83C\\uDD95',\n init: '\\uD83C\\uDFC1'\n }[t])\n },\n layout: 'auto',\n sort: 't',\n reverse: true,\n required: false\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2063,"value":"rewind ? Inputs.button(`rewind to ${ new Date(rewind).toISOString() }`, { reduce: () => rewindToTime(rewind) }) : md`⚠️ pick a time to rewind`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2064,"value":"selectedChanges.length ? Inputs.button('revert variables', { reduce: () => revertVariables(selectedChanges) }) : md`⚠️ select some variables to revert individual cells`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2065,"value":"md`## History Data Model\n\nThe primary data is history with an array of history entries. Each has the following fields.\n\n~~~js\n{\n t // epoch time\n op // operation: new, del, upd\n pid // variable persistent id (see runtime-sdk, persists across exports)\n source // runtime, module, git\n provenance // additional write metadata\n\n // Then we serialize new fields on the variable\n _name, // string or null\n _inputs, // array of strings\n _definition // is the toString not a live reference\n}\n~~~\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2066,"value":"$33","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2067,"value":"md`## Replay and Save Algorithm\n\nOn page refresh, the notebook will load in a state that does not have the latest changes, so we need to replay to catch up.\n\nWe want to display the full history of all changes, so we also need to scan the git history.\n\nWe also want to capture any future changes and save them for git. We have to be careful that we don't accidentally capture our own replays as new changes.\n\n\n1. Replay latest git values to notebook\n tag definition with provenance (historical timestamp, source: git)\n3. Scan git message history to figure out the git sourced change log (including historical timestamps).\n4. *add a listener for *new changes* made to the runtime\n - on change, commit to git, if it did not come from git`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2068,"value":"md`## Persistent Variable IDs\n\nVariables \\`definitions\\` are tagged with a persistent id (pid) so we can track what change applies to what variable. This does not work on Observablehq.com, which has a first party history feature anyway. This work only makes sense in the context of [Lopecode](https://github.com/tomlarkworthy/lopecode), if you want to try it out, you can convert his notebook to Lopecode with Jumpgate`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2069,"value":"md`## Git Replay\n\n`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2070,"value":"git_commits = (await listCommits(config)).map(v => ({\n ...v,\n summary: JSON.parse(v.commit.message)\n}))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2071,"value":"$34","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2072,"value":"notebookCreationTime = {\n const timesSec = (git_commits ?? []).map(h => h?.commit?.committer?.timestamp ?? h?.commit?.author?.timestamp ?? null).filter(t => t != null);\n if (timesSec.length)\n return Math.min(...timesSec) * 1000 - 1000;\n return Date.now() - 1000;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2073,"value":"$35","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2074,"value":"$36","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2075,"value":"replay_pid_map = new Map()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2076,"value":"$37","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2077,"value":"$38","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2078,"value":"replay_git = {\n if (isOnObservableCom())\n return [];\n // doesn't work on Observablehq\n modules;\n return replayGitCommits(relevant_git_commits, { order: 'oldest-first' });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2079,"value":"md`## IndexDB State Explorer`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2080,"value":"Inputs.button('download git zip', {\n reduce: async () => {\n const zip = await exportToZip({\n fs,\n dir: config.repo\n });\n const url = URL.createObjectURL(zip);\n const a = document.createElement('a');\n a.href = url;\n a.download = `history_${ getCompactISODate() }.zip`;\n a.click();\n URL.revokeObjectURL(url);\n }\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2081,"value":"repos = listRepos()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2082,"value":"branches = listBranches({ repo: selected_repo })","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2083,"value":"selected_files = listFiles({\n repo: selected_repo,\n branch: selected_branch\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2084,"value":"Inputs.table(selected_files.map(path => ({ path })))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2085,"value":"selected_commits = listCommits({\n repo: selected_repo,\n branch: selected_branch\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2086,"value":"Inputs.table(selected_commits, { format: { commit: commit => JSON.stringify(commit, null, 2) } })","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2087,"value":"exportFsToZip = async function exportFsToZip({fs, dir} = {}) {\n if (!fs)\n throw new Error('exportFsToZip: fs is required');\n if (!dir)\n throw new Error('exportFsToZip: dir is required');\n if (!JSZip)\n throw new Error('exportFsToZip: JSZip is not available');\n const zip = new JSZip();\n async function walk(currentPath, relPath = '') {\n const names = await fs.readdir(currentPath);\n for (const name of names) {\n if (name === '.' || name === '..')\n continue;\n const fullPath = (currentPath.endsWith('/') ? currentPath : currentPath + '/') + name;\n const childRelPath = relPath ? relPath + '/' + name : name;\n const stat = await fs.stat(fullPath);\n if (stat.type === 'file') {\n const data = await fs.readFile(fullPath);\n zip.file(childRelPath, data);\n } else if (stat.type === 'dir') {\n await walk(fullPath, childRelPath);\n }\n }\n }\n await walk(dir, '');\n return zip.generateAsync({ type: 'blob' });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2088,"value":"md`### Git utils`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2089,"value":"known_dirs = fs && new Set()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2090,"value":"ensure_dir = async function ensure_dir({dir}) {\n if (known_dirs.has(dir))\n return;\n if (!dir || dir === '/')\n return;\n const lastSlash = dir.lastIndexOf('/');\n const parent = lastSlash > 0 ? dir.slice(0, lastSlash) : '/';\n if (parent && parent !== dir) {\n await ensure_dir({ dir: parent });\n }\n try {\n await fs.mkdir(dir);\n } catch (err) {\n if (!(err && err.message === 'EEXIST')) {\n throw err;\n }\n }\n known_dirs.add(dir);\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2091,"value":"known_repos = fs && new Set()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2092,"value":"ensure_repo = {\n return async ({repo, defaultBranch = 'default'}) => {\n if (known_repos.has(repo))\n return;\n await ensure_dir({ dir: repo });\n await git.init({\n fs,\n dir: repo,\n bare: false,\n // We should switch to this but we need to set gitdir everywhere\n defaultBranch\n });\n fs.flush();\n known_repos.add(repo);\n };\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2093,"value":"ensure_branch = async ({repo, branch, create = true} = {}) => {\n if (!repo)\n throw new Error('ensure_branch: repo is required');\n if (!branch)\n throw new Error('ensure_branch: branch is required');\n await ensure_repo({\n repo,\n defaultBranch: branch\n });\n const branches = await listBranches({ repo });\n const hasBranch = branches.includes(branch);\n if (!hasBranch && create) {\n try {\n await git.branch({\n fs,\n dir: repo,\n ref: 'refs/heads/' + branch,\n checkout: false\n });\n } catch (err) {\n if (err.toString().includes('it already exists'))\n return true;\n throw err;\n }\n return true;\n }\n if (!hasBranch)\n return false;\n return true;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2094,"value":"$39","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2095,"value":"setFileAndCommit = async function setFileAndCommit({repo, branch, path, content}) {\n return await setFilesAndCommit({\n repo,\n branch,\n data: new Map([[\n path,\n content\n ]])\n });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2096,"value":"$3a","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2097,"value":"$3b","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2098,"value":"listBranches = async function listBranches({repo} = {}) {\n if (!repo)\n throw new Error('repo is required');\n await ensure_repo({ repo });\n try {\n return await git.listBranches({\n fs,\n dir: repo\n });\n } catch (e) {\n return [];\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2099,"value":"listFiles = async function listFiles({repo, branch, ref} = {}) {\n if (!repo)\n throw new Error('repo is required');\n if (!branch)\n throw new Error('branch is required');\n try {\n await ensure_branch({\n repo,\n branch,\n create: true\n });\n return await git.listFiles({\n fs,\n dir: repo,\n ref: ref ?? branch\n });\n } catch (err) {\n console.error(err);\n return [];\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2100,"value":"listCommits = async function listCommits({repo, branch, depth} = {}) {\n if (!repo)\n throw new Error('repo is required');\n if (!branch)\n throw new Error('branch is required');\n const hasBranch = await ensure_branch({\n repo,\n branch,\n create: false\n });\n if (!hasBranch)\n return [];\n return git.log({\n fs,\n dir: repo,\n ref: branch,\n depth\n });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2101,"value":"$3c","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2102,"value":"getCompactISODate = function getCompactISODate() {\n const date = new Date();\n const year = date.getUTCFullYear();\n const month = String(date.getUTCMonth() + 1).padStart(2, '0');\n const day = String(date.getUTCDate()).padStart(2, '0');\n const hours = String(date.getUTCHours()).padStart(2, '0');\n const minutes = String(date.getUTCMinutes()).padStart(2, '0');\n const seconds = String(date.getUTCSeconds()).padStart(2, '0');\n return `${ year }${ month }${ day }T${ hours }${ minutes }${ seconds }Z`;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2103,"value":"exportToZip = async function exportToZip({fs, dir}) {\n const zip = new JSZip();\n async function walk(currentPath, relPath = '') {\n const names = await fs.readdir(currentPath);\n for (const name of names) {\n if (name === '.' || name === '..')\n continue;\n const fullPath = (currentPath.endsWith('/') ? currentPath : currentPath + '/') + name;\n const childRelPath = relPath ? relPath + '/' + name : name;\n const stat = await fs.stat(fullPath);\n if (stat.type === 'file') {\n const data = await fs.readFile(fullPath);\n zip.file(childRelPath, data);\n } else if (stat.type === 'dir') {\n await walk(fullPath, childRelPath);\n }\n }\n }\n await walk(dir, '');\n return zip.generateAsync({ type: 'blob' });\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2104,"value":"md`### Provenance Utils`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2105,"value":"tag = function tag(def, provenance) {\n if (def == null)\n return def;\n const p = provenance && typeof provenance === 'object' ? { ...provenance } : { value: provenance };\n try {\n if (typeof def === 'function' || typeof def === 'object' && def !== null) {\n Object.defineProperty(def, '__provenance', {\n value: p,\n configurable: true\n });\n return def;\n }\n } catch {\n }\n return def;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2106,"value":"read = function read(def) {\n if (def == null)\n return null;\n try {\n return def.__provenance ?? null;\n } catch {\n return null;\n }\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2107,"value":"md`## History API Functions`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2108,"value":"$3d","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2109,"value":"rewindToTime = {\n return function rewindToTime(time) {\n // history is sorted ascending by t; index = number of changes at or before `time`\n let index = 0;\n for (const entry of history) {\n if ((entry?.t ?? 0) <= time)\n index++;\n else\n break;\n }\n return applyHistoryState(index);\n };\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2110,"value":"md`## State`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2111,"value":"config = {\n const url = new URL(document.baseURI);\n const config = {\n repo: '/' + notebook_title,\n branch: (url.origin + url.pathname).replace(/[.:/]/g, '_')\n };\n await ensure_branch(config);\n return config;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2112,"value":"historyUtils = ({\n snapshotVariable(v) {\n if (!v)\n return null;\n const name = typeof v._name === 'string' && v._name.length ? v._name : null;\n const inputsRaw = Array.isArray(v._inputs) ? v._inputs : [];\n const inputs = inputsRaw.map(i => typeof i === 'string' ? i : i?._name).filter(x => x != null);\n const def = v._definition;\n const _definition = typeof def === 'function' ? def.toString() : def == null ? '' : String(def);\n return {\n _name: name,\n _inputs: inputs,\n _definition\n };\n },\n insertByTime(arr, entry) {\n const t = entry?.t ?? 0;\n let lo = 0, hi = arr.length;\n while (lo < hi) {\n const mid = lo + hi >> 1;\n const mt = arr[mid]?.t ?? 0;\n if (mt <= t)\n lo = mid + 1;\n else\n hi = mid;\n }\n arr.splice(lo, 0, entry);\n return lo;\n }\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2113,"value":"$3e","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2114,"value":"Inputs.table(history, {\n sort: 't',\n reverse: true\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2115,"value":"md`## Commit History`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2116,"value":"commit_watermarks = new Map()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2117,"value":"$3f","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2118,"value":"$40","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2119,"value":"commit_history = commitRuntimeHistorySince({\n ...config,\n history\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2120,"value":"md`## Utils`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2121,"value":"identity = (await lookupVariable('lookupVariable', historyModule))._definition","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2122,"value":"modules = moduleMap()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2123,"value":"timeline = {\n const first = history.at(0)?.t ?? 0;\n const last = history.at(-1)?.t ?? 0;\n const factor = Math.max(last - first, 1) / 1024;\n return Array.from({ length: 1024 }).map((_, i) => Math.floor(first + i * factor));\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2124,"value":"moduleBaseHash = {\n const hash = s => {\n s = String(s);\n let h = 2166136261;\n for (let i = 0; i < s.length; i++)\n h = Math.imul(h ^ s.charCodeAt(i), 16777619);\n return '_' + (h >>> 0).toString(36);\n };\n return function moduleBaseHash(moduleName) {\n const script = document.getElementById(moduleName);\n if (!script)\n return null;\n return hash(script.textContent);\n };\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2125,"value":"viewof history = Inputs.input([])","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2126,"value":"viewof fs = Inputs.button('wipe filesystem', {\n reduce: () => new FS('lopecode_history', { wipe: true }).promises,\n value: new FS('lopecode_history', { wipe: false }).promises\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2127,"value":"viewof selected_repo = Inputs.select(repos, {\n label: 'select repo',\n value: config.repo\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2128,"value":"viewof selected_branch = Inputs.select(branches, {\n label: 'select branch',\n value: selected_repo == config.repo ? config.branch : undefined\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2129,"value":"viewof initial_state = Inputs.input(new Map())","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2130,"value":"viewof module_load_time = Inputs.input(new Map())","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2131,"value":"viewof historyModule = thisModule()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2132,"value":"import { thisModule, lookupVariable, onCodeChange, runtime, persistentId, getVariableByPersistentId, isOnObservableCom, realize } from \"@tomlarkworthy/runtime-sdk\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2133,"value":"import { FS } from \"@tomlarkworthy/lightning-fs-4-6-0\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2134,"value":"import { git, http } from \"@tomlarkworthy/isomorphic-git-1-30-1\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2135,"value":"import { JSZip } from \"@tomlarkworthy/jszip-3-10-1\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2136,"value":"import { moduleMap } from \"@tomlarkworthy/module-map\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2137,"value":"import { notebook_title } from \"@tomlarkworthy/exporter-3\"","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2221,"value":"$41","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2222,"value":"$42","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":2223,"value":"playback_suspend = ({ until: 0 })","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W43","stdlib":"1","titling":"auto"}} 32:"$31:body"