blob: c6733776242f834e5fb6ef2c0f8fc7e6a34ba8ca (
plain)
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;(function() {
if(typeof Blob === 'undefined')
return console.warn('Screw-FileReader is only meant to work in those' +
'engine who already has some basic support for blob')
var blob = Blob.prototype
var fullStreamSupport = false
var basicStreamSupport = false
var fetchTransform = false
var URL = window.URL || window.webkitURL
function promisify(obj) {
return new Promise(function(resolve, reject) {
obj.onload =
obj.onerror = function(evt) {
obj.onload =
obj.onerror = null
evt.type === 'load'
? resolve(obj.result || obj)
: reject(obj.error)
}
})
}
function toImage(url) {
var img = new Image
img.src = url
return promisify(img)
}
try {
new ReadableStream({})
basicStreamSupport = true
} catch (e) {}
try {
new ReadableStream({type: 'bytes'})
fullStreamSupport = true
} catch (e) {}
try {
(new Response(new Blob)).getReader()
fetchTransform = true
} catch (e) {}
if(!blob.arrayBuffer) {
blob.arrayBuffer = function arrayBuffer() {
var fr = new FileReader
fr.readAsArrayBuffer(this)
return promisify(fr)
}
}
if(!blob.text) {
blob.text = function text() {
var fr = new FileReader
fr.readAsText(this)
return promisify(fr)
}
}
if(!blob.dataURL) {
blob.dataURL = function dataURL() {
var fr = new FileReader
fr.readAsDataURL(this)
return promisify(fr)
}
}
if(!blob.url) {
blob.url = function url() {
return URL ? URL.createObjectURL(this) : null
}
}
if(!blob.json) {
blob.json = function json() {
return this.text().then(JSON.parse)
}
}
if(!blob.image) {
blob.image = function image() {
return Promise.resolve(this.url() || this.dataURL()).then(toImage)
}
}
if(!blob.stream) {
blob.stream =
fullStreamSupport ? function stream() {
var position = 0
var blob = this
return new ReadableStream({
type: 'bytes',
autoAllocateChunkSize: 524288,
pull: function (controller) {
var v = controller.byobRequest.view
var chunk = blob.slice(position, position + v.byteLength)
return chunk.arrayBuffer()
.then(function (buffer) {
let uint8array = new Uint8Array(buffer)
let bytesRead = uint8array.byteLength
position += bytesRead
v.set(uint8array)
controller.byobRequest.respond(bytesRead)
if(position >= blob.size)
controller.close()
})
}
})
}:
// basic stream support
basicStreamSupport ? function stream(blob){
var position = 0
var blob = this
return new ReadableStream({
pull: function (controller) {
var chunk = blob.slice(position, position + 524288)
return chunk.arrayBuffer().then(function (buffer) {
position += buffer.byteLength
let uint8array = new Uint8Array(buffer)
controller.enqueue(uint8array)
if(position == blob.size)
controller.close()
})
}
})
}:
// fetchTransform
fetchTransform ? function stream() {
return (new Response(this)).body
}:
function stream() {
throw new Error('Include https://github.com/creatorrr/web-streams-polyfill')
}
}
}());
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