30:[] 2e:{"title":"Base64","cells":[{"id":0,"value":"# Base64","pinned":false,"hidden":false,"mode":"md"},{"id":3,"value":"viewof encoded = Inputs.textarea({\n value: \"RWRpdCBtZSwgb3IgcGFzdGUgc29tZSBCYXNlNjQgaW50byB0aGUgYm94IGFib3ZlIQ==\",\n spellcheck: false,\n label: \"Encoded\"\n})","pinned":false,"hidden":false,"mode":"ojs"},{"id":6,"value":"viewof decoded = Inputs.textarea({\n label: \"Decoded\",\n spellcheck: false\n})","pinned":false,"hidden":false,"mode":"ojs"},{"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"},{"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"},{"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"},{"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"},{"id":90,"value":"chars = \"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/\"","pinned":true,"hidden":false,"mode":"ojs"},{"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"}],"files":"$W30","stdlib":"1","titling":"auto"}