2d:null 2e:["$","title",null,{"children":"Base64 | Mike Bostock | Observable"}] 33:[] 31:{"id":"cb60908738c3dabe","slug":"base64","title":"Base64","thumbnail":"8576db5df78cd6b905e728b37e6f56eb01f56d8df3dbce259a8c4bbf0cdd1c2c","access_level":"public","create_time":"$D2018-08-09T21:22:39.744Z","update_time":"$D2022-03-17T03:29:59.744Z","view_time":null,"first_public_time":"$D2018-08-09T21:36:50.453Z","fork":false,"stars":10,"starred":false,"owner":{"type":"team","id":"8c2e47252fd4995c","login":"mbostock","name":"Mike Bostock","avatar_url":"https://avatars-next.observableusercontent.com/7dbba99ced40bd5ab8013c99b1a11da61231bce321ba1148a9d16ad0f121550a","tier":"pro_2026"},"version":152,"publish_version":152,"role":null,"authored":false,"authors":[{"type":"individual","id":"074c414ad1d825f5","login":"mbostock","name":"Mike Bostock","avatar_url":"https://avatars-next.observableusercontent.com/7dbba99ced40bd5ab8013c99b1a11da61231bce321ba1148a9d16ad0f121550a","tier":null}],"members":[{"type":"individual","id":"074c414ad1d825f5","login":"mbostock","name":"Mike Bostock","avatar_url":"https://avatars-next.observableusercontent.com/7dbba99ced40bd5ab8013c99b1a11da61231bce321ba1148a9d16ad0f121550a","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":8,"collection":{"id":"dfdfb0e58dceb865","slug":"applications","title":"Applications","owner":{"id":"8c2e47252fd4995c","login":"mbostock","name":"Mike Bostock"}},"type":"notebook","body":{"title":"Base64","cells":[{"id":0,"value":"# Base64","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":3,"value":"viewof encoded = Inputs.textarea({\n value: \"RWRpdCBtZSwgb3IgcGFzdGUgc29tZSBCYXNlNjQgaW50byB0aGUgYm94IGFib3ZlIQ==\",\n spellcheck: false,\n label: \"Encoded\"\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":6,"value":"viewof decoded = Inputs.textarea({\n label: \"Decoded\",\n spellcheck: false\n})","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":94,"value":"---\n\n## Implementation\n\nBased on Niklas von Hertzen’s [base64-arraybuffer](https://github.com/niklasvh/base64-arraybuffer); MIT licensed.","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined","output":"","database":"$undefined"},{"id":131,"value":"update = {\n const decoder = new TextDecoder(\"utf-8\");\n const encoder = new TextEncoder(\"utf-8\");\n const redecode = () => viewof decoded.value = decoder.decode(decode(viewof encoded.value));\n const reencode = () => viewof encoded.value = encode(encoder.encode(viewof decoded.value));\n redecode();\n viewof encoded.addEventListener(\"input\", redecode);\n viewof decoded.addEventListener(\"input\", reencode);\n invalidation.then(() => {\n viewof encoded.removeEventListener(\"input\", redecode);\n viewof decoded.removeEventListener(\"input\", reencode);\n });\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":92,"value":"function decode(base64) {\n let len = base64.length;\n let bufferLength = len * 0.75;\n let i;\n let p = 0;\n if (base64[base64.length - 1] === \"=\") {\n --bufferLength;\n if (base64[base64.length - 2] === \"=\") {\n --bufferLength;\n }\n }\n let bytes = new Uint8Array(bufferLength);\n for (i = 0; i < len; i+=4) {\n const encoded1 = lookup[base64.charCodeAt(i)];\n const encoded2 = lookup[base64.charCodeAt(i+1)];\n const encoded3 = lookup[base64.charCodeAt(i+2)];\n const encoded4 = lookup[base64.charCodeAt(i+3)];\n bytes[p++] = (encoded1 << 2) | (encoded2 >> 4);\n bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2);\n bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63);\n }\n return bytes.buffer;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":91,"value":"function encode(buffer) {\n let bytes = new Uint8Array(buffer);\n let len = bytes.length;\n let i;\n let base64 = \"\";\n for (i = 0; i < len; i+=3) {\n base64 += chars[bytes[i] >> 2];\n base64 += chars[((bytes[i] & 3) << 4) | (bytes[i + 1] >> 4)];\n base64 += chars[((bytes[i + 1] & 15) << 2) | (bytes[i + 2] >> 6)];\n base64 += chars[bytes[i + 2] & 63];\n }\n if ((len % 3) === 2) {\n base64 = base64.slice(0, -1) + \"=\";\n } else if (len % 3 === 1) {\n base64 = base64.slice(0, -2) + \"==\";\n }\n return base64;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":90,"value":"chars = \"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/\"","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":89,"value":"lookup = {\n const lookup = new Uint8Array(256);\n for (let i = 0; i < chars.length; i++) {\n lookup[chars.charCodeAt(i)] = i;\n }\n return lookup;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W33","stdlib":"1","titling":"auto"}} 32:"$31:body"