133 lines
2.8 KiB
JavaScript
133 lines
2.8 KiB
JavaScript
// Based on https://github.com/tmpvar/jsdom/blob/aa85b2abf07766ff7bf5c1f6daafb3726f2f2db5/lib/jsdom/living/blob.js
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// (MIT licensed)
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const {Readable} = require('stream');
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const BUFFER = Symbol('buffer');
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const TYPE = Symbol('type');
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class Blob {
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constructor(...args) {
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this[TYPE] = '';
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const blobParts = args[0];
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const options = args[1];
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const buffers = [];
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/* eslint-disable-next-line no-unused-vars */
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let size = 0;
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if (blobParts) {
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blobParts.forEach(element => {
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let buffer;
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if (element instanceof Buffer) {
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buffer = element;
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} else if (ArrayBuffer.isView(element)) {
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buffer = Buffer.from(element.buffer, element.byteOffset, element.byteLength);
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} else if (element instanceof ArrayBuffer) {
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buffer = Buffer.from(element);
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} else if (element instanceof Blob) {
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buffer = element[BUFFER];
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} else {
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buffer = Buffer.from(typeof element === 'string' ? element : String(element));
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}
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size += buffer.length;
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buffers.push(buffer);
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});
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}
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this[BUFFER] = Buffer.concat(buffers);
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const type = options && options.type !== undefined && String(options.type).toLowerCase();
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if (type && !/[^\u0020-\u007E]/.test(type)) {
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this[TYPE] = type;
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}
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if (options && Buffer.isBuffer(options.buffer)) {
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this[BUFFER] = options.buffer;
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}
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}
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get size() {
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return this[BUFFER].length;
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}
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get type() {
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return this[TYPE];
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}
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text() {
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return Promise.resolve(this[BUFFER].toString());
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}
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arrayBuffer() {
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const buf = this[BUFFER];
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const ab = buf.buffer.slice(buf.byteOffset, buf.byteOffset + buf.byteLength);
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return Promise.resolve(ab);
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}
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stream() {
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const readable = new Readable();
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readable._read = () => { };
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readable.push(this[BUFFER]);
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readable.push(null);
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return readable;
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}
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toString() {
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return '[object Blob]';
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}
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slice(...args) {
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const {size} = this;
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const start = args[0];
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const end = args[1];
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let relativeStart;
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let relativeEnd;
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if (start === undefined) {
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relativeStart = 0;
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} else if (start < 0) {
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relativeStart = Math.max(size + start, 0);
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} else {
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relativeStart = Math.min(start, size);
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}
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if (end === undefined) {
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relativeEnd = size;
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} else if (end < 0) {
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relativeEnd = Math.max(size + end, 0);
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} else {
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relativeEnd = Math.min(end, size);
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}
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const span = Math.max(relativeEnd - relativeStart, 0);
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const buffer = this[BUFFER];
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const slicedBuffer = buffer.slice(
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relativeStart,
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relativeStart + span
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);
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const blob = new Blob([], {type: args[2]});
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blob[BUFFER] = slicedBuffer;
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return blob;
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}
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}
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Object.defineProperties(Blob.prototype, {
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size: {enumerable: true},
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type: {enumerable: true},
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slice: {enumerable: true}
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});
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Object.defineProperty(Blob.prototype, Symbol.toStringTag, {
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value: 'Blob',
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writable: false,
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enumerable: false,
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configurable: true
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});
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module.exports = Blob;
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