10 examples of 'blob to base64' in JavaScript

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function blobToBase64(blob, cb) {
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  var reader = new FileReader();
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  reader.onload = function() {
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    var dataUrl = reader.result;
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    var base64 = dataUrl.split(',')[1];
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    cb(base64);
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  };
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  reader.readAsDataURL(blob);
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}

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function blobToBase64(blobOrBuffer, callback) {
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  blobOrBufferToBinaryString(blobOrBuffer, function (base64) {
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    callback(btoa(base64));
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  });
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}

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function base64ToBlob_(base64, mimetype) {
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  var BASE64_MARKER = ';base64,';
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  var raw = window.atob(base64);
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  var rawLength = raw.length;
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  var uInt8Array = new Uint8Array(rawLength);
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  for (var i = 0; i < rawLength; ++i) {
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    uInt8Array[i] = raw.charCodeAt(i);
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  }
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  if (imagelib.util.hasBlobConstructor()) {
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    return new Blob([uInt8Array], {type: mimetype})
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  }
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  var bb = new BlobBuilder();
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  bb.append(uInt8Array.buffer);
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  return bb.getBlob(mimetype);
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}

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decodeBlob(blob) {
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    return this.getClass().decodeBlob(blob);
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}

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export function base64ToBlob(base64: string): Blob {
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  const sliceSize = 1024
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  const byteChars = globalThis.atob(base64)
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  const byteArrays = []
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  let len = byteChars.length
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  for (let offset = 0; offset < len; offset += sliceSize) {
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    const slice = byteChars.slice(offset, offset + sliceSize)
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    const byteNumbers = new Array(slice.length)
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    for (let i = 0; i < slice.length; i++) {
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      byteNumbers[i] = slice.charCodeAt(i)
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    }
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    const byteArray = new Uint8Array(byteNumbers)
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    byteArrays.push(byteArray)
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    len = byteChars.length
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  }
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  return new Blob(byteArrays, { type: 'image/jpeg' })
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}

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function base64DataUriToBlob(url) {
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	// 5 is length of "data:" prefix
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	var mime = url.substr(5, url.indexOf(';') - 5);
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	var data = atob(url.substr(url.indexOf(',') + 1));
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	/* global Uint8Array */
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	var binary = new Uint8Array(data.length);
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	for (var i = 0; i < data.length; i++) {
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		binary[i] = data[i].charCodeAt(0);
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	}
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	try {
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		return new Blob([binary], { type: mime });
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	} catch (e) {
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		return null;
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	}
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}

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function blobToBase64Png(image) {
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  var png = image.getImage();
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  var chunks = [];
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  return new Promise(function(resolve) {
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    png.pack();
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    png.on('data', function(chunk) {
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      chunks.push(chunk);
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    });
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    png.on('end', function() {
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      var result = Buffer.concat(chunks);
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      resolve('data:image/png;base64,' + result.toString('base64'));
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    });
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  });
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}

23
function base64ToBlob(data) {
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    var mimeString = '';
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    var raw, uInt8Array, i, rawLength;
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    raw = data.replace(rImageType, function(header, imageType) {
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        mimeString = imageType;
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        return '';
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    });
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    raw = atob(raw);
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    rawLength = raw.length;
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    uInt8Array = new Uint8Array(rawLength); // eslint-disable-line
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    for (i = 0; i < rawLength; i += 1) {
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        uInt8Array[i] = raw.charCodeAt(i);
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    }
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    return new Blob([uInt8Array], {type: mimeString});
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}

173
function blobToBase64String(blob) {
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  return blobToBinaryString(blob).then(function (binary) {
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    return btoa(binary);
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  });
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}

35
b64toBlob: function b64toBlob(b64) {
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  return new Promise((resolve, reject) => {
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    var img = new Image();
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    img.onload = function onload() {
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      var canvas = document.createElement('canvas');
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      canvas.width = img.width;
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      canvas.height = img.height;
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      var ctx = canvas.getContext('2d');
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      ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
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      canvas.toBlob(resolve);
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    };
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    img.onerror = reject;
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    img.src = b64;
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  });
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},