Published
Edited
Mar 4, 2022
Importers
15 stars
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editor
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viewof CM = loadCodeMirror({view: true, modes: ['javascript', 'sparql', 'clike'], themes: [themeObservableURL, ...themes]})
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async function loadCodeMirror(options = {}) {
const {
version = 'latest',
themes = [],
modes = [],
minify = true,
view = false,
viewLabel = (version, modes, themes) => `CodeMirror ${version}${!modes.length ? '' : ` (${modes.join(', ')})`}`,
} = options;
// d3-require uses jsdelivr.com by default, which in turn allows
// us to minify files by attaching ".min" to filenames.
const suffix = minify ? '.min' : '';
// Adding "." to the end keeps d3-require from appending ".js" to the path.
const PATH = (await require.resolve(`codemirror@${version}/.`)).slice(0, -2);
const cm = require(`${PATH}/lib/codemirror${suffix}.js`).then(cm => {
if(!modes.length) return cm;
// Mode scripts reference CodeMirror via "../../lib/codemirror".
// To maintain encapsulation we alias that path to our already resolved CM package.
return require.alias({'../../lib/codemirror': cm})(
// Expand mode URLs and pass to our aliased require().
...modes.map(mode => `${PATH}/mode/${mode}/${mode}${suffix}.js`)
)
// The mode scripts modify our CM directly, so only the instance needs to be returned.
.then(() => cm);
});
// While the scripts are loading, let's load the CSS as well.
const isUrl = str => {
try { new URL(str); return true }
catch(e) { return false }
};
const fetchText = async url => {
const r = await fetch(url);
if(!r.ok) throw Error(`${r.status} (${url})`);
return r.text();
};
const css = Promise.all([
// The editor stylesheet.
fetchText(`${PATH}/lib/codemirror${suffix}.css`),
// Expand theme stylesheet URLs.
...themes.map(name => fetchText(isUrl(name) ? name : `${PATH}/theme/${name}${suffix}.css`))
]);
// Wait until all scripts and stylesheets are loaded.
return Promise.all([cm, css]).then(([cm, css]) => {
// Conveniently concat CSS contents on string conversion.
Object.assign(css, { toString() { return this.join('\n') } });
if(view) return Object.defineProperty(
html`<pre>${viewLabel(cm.version, modes, themes)}</pre><style>${css}`,
'value',
{ value: cm }
);
// Attach the CSS, but keep the file contents separated.
cm.CSS = css;
return cm;
});
}
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One platform to build and deploy the best data apps

Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
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