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'use strict'
const { Minipass } = require('minipass')
const TYPE = Symbol('type')
const BUFFER = Symbol('buffer')
class Blob {
constructor (blobParts, options) {
this[TYPE] = ''
const buffers = []
let size = 0
if (blobParts) {
const a = blobParts
const length = Number(a.length)
for (let i = 0; i < length; i++) {
const element = a[i]
const buffer = element instanceof Buffer ? element
: ArrayBuffer.isView(element)
? Buffer.from(element.buffer, element.byteOffset, element.byteLength)
: element instanceof ArrayBuffer ? Buffer.from(element)
: element instanceof Blob ? element[BUFFER]
: typeof element === 'string' ? Buffer.from(element)
: Buffer.from(String(element))
size += buffer.length
buffers.push(buffer)
}
}
this[BUFFER] = Buffer.concat(buffers, size)
const type = options && options.type !== undefined
&& String(options.type).toLowerCase()
if (type && !/[^\u0020-\u007E]/.test(type)) {
this[TYPE] = type
}
}
get size () {
return this[BUFFER].length
}
get type () {
return this[TYPE]
}
text () {
return Promise.resolve(this[BUFFER].toString())
}
arrayBuffer () {
const buf = this[BUFFER]
const off = buf.byteOffset
const len = buf.byteLength
const ab = buf.buffer.slice(off, off + len)
return Promise.resolve(ab)
}
stream () {
return new Minipass().end(this[BUFFER])
}
slice (start, end, type) {
const size = this.size
const relativeStart = start === undefined ? 0
: start < 0 ? Math.max(size + start, 0)
: Math.min(start, size)
const relativeEnd = end === undefined ? size
: end < 0 ? Math.max(size + end, 0)
: Math.min(end, size)
const span = Math.max(relativeEnd - relativeStart, 0)
const buffer = this[BUFFER]
const slicedBuffer = buffer.slice(
relativeStart,
relativeStart + span
)
const blob = new Blob([], { type })
blob[BUFFER] = slicedBuffer
return blob
}
get [Symbol.toStringTag] () {
return 'Blob'
}
static get BUFFER () {
return BUFFER
}
}
Object.defineProperties(Blob.prototype, {
size: { enumerable: true },
type: { enumerable: true },
})
module.exports = Blob
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