97 lines
2.3 KiB
JavaScript
97 lines
2.3 KiB
JavaScript
'use strict'
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const Minipass = require('minipass')
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const TYPE = Symbol('type')
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const BUFFER = Symbol('buffer')
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class Blob {
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constructor (blobParts, options) {
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this[TYPE] = ''
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const buffers = []
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let size = 0
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if (blobParts) {
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const a = blobParts
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const length = Number(a.length)
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for (let i = 0; i < length; i++) {
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const element = a[i]
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const buffer = element instanceof Buffer ? element
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: ArrayBuffer.isView(element)
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? Buffer.from(element.buffer, element.byteOffset, element.byteLength)
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: element instanceof ArrayBuffer ? Buffer.from(element)
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: element instanceof Blob ? element[BUFFER]
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: typeof element === 'string' ? Buffer.from(element)
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: Buffer.from(String(element))
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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, size)
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const type = options && options.type !== undefined
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&& 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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}
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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 off = buf.byteOffset
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const len = buf.byteLength
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const ab = buf.buffer.slice(off, off + len)
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return Promise.resolve(ab)
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}
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stream () {
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return new Minipass().end(this[BUFFER])
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}
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slice (start, end, type) {
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const size = this.size
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const relativeStart = start === undefined ? 0
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: start < 0 ? Math.max(size + start, 0)
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: Math.min(start, size)
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const relativeEnd = end === undefined ? size
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: end < 0 ? Math.max(size + end, 0)
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: Math.min(end, size)
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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 })
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blob[BUFFER] = slicedBuffer
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return blob
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}
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get [Symbol.toStringTag] () {
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return 'Blob'
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}
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static get BUFFER () {
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return BUFFER
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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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})
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module.exports = Blob
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