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Updated b64toByteArrays function to improve performance #97

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Updated b64toByteArrays function to improve performance #97

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44 changes: 21 additions & 23 deletions src/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -91,38 +91,36 @@ class Resizer {
return canvas.toDataURL(`image/${compressFormat}`, qualityDecimal);
}

static b64toByteArrays(b64Data, contentType) {
contentType = contentType || "image/jpeg";
var sliceSize = 512;

var byteCharacters = atob(
b64Data.toString().replace(/^data:image\/(png|jpeg|jpg|webp);base64,/, "")
);
var byteArrays = [];

for (var offset = 0; offset < byteCharacters.length; offset += sliceSize) {
var slice = byteCharacters.slice(offset, offset + sliceSize);

var byteNumbers = new Array(slice.length);
for (var i = 0; i < slice.length; i++) {
byteNumbers[i] = slice.charCodeAt(i);
}

var byteArray = new Uint8Array(byteNumbers);

byteArrays.push(byteArray);
static b64toByteArrays(b64Data) {
const sliceSize = 1024; // 1024 gives best performance
const base64Marker = /^data:image\/(png|jpeg|jpg|webp);base64,/;

const byteCharacters = atob(b64Data.replace(base64Marker, ""));
const byteLength = byteCharacters.length;
const byteArrays = [];

for (let offset = 0; offset < byteLength; offset += sliceSize) {
const sliceLength = Math.min(sliceSize, byteLength - offset);
const byteArray = new Uint8Array(sliceLength);

for (let i = 0; i < sliceLength; i++) {
byteArray[i] = byteCharacters.charCodeAt(offset + i);
}

byteArrays.push(byteArray);
}

return byteArrays;
}
}

static b64toBlob(b64Data, contentType) {
const byteArrays = this.b64toByteArrays(b64Data, contentType);
const byteArrays = this.b64toByteArrays(b64Data);
var blob = new Blob(byteArrays, { type: contentType, lastModified: new Date() });
return blob;
}

static b64toFile(b64Data, fileName, contentType) {
const byteArrays = this.b64toByteArrays(b64Data, contentType);
const byteArrays = this.b64toByteArrays(b64Data);
const file = new File(byteArrays, fileName, { type: contentType, lastModified: new Date() });
return file;
}
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