shuquAi/utils/FileSaver.js

/*
 * FileSaver.js
 * A saveAs() FileSaver implementation.
 *
 * By Eli Grey, http://eligrey.com
 *
 * License : https://github.com/eligrey/FileSaver.js/blob/master/LICENSE.md (MIT)
 * source  : http://purl.eligrey.com/github/FileSaver.js
 */

// The one and only way of getting global scope in all environments
// https://stackoverflow.com/q/3277182/1008999
var _global = typeof window === 'object' && window.window === window ?
	window : typeof self === 'object' && self.self === self ?
	self : typeof global === 'object' && global.global === global ?
	global :
	this

function bom(blob, opts) {
	if (typeof opts === 'undefined') opts = {
		autoBom: false
	}
	else if (typeof opts !== 'object') {
		console.warn('Deprecated: Expected third argument to be a object')
		opts = {
			autoBom: !opts
		}
	}

	// prepend BOM for UTF-8 XML and text/* types (including HTML)
	// note: your browser will automatically convert UTF-16 U+FEFF to EF BB BF
	if (opts.autoBom && /^\s*(?:text\/\S*|application\/xml|\S*\/\S*\+xml)\s*;.*charset\s*=\s*utf-8/i.test(blob.type)) {
		return new Blob([String.fromCharCode(0xFEFF), blob], {
			type: blob.type
		})
	}
	return blob
}

function download(url, name, opts) {
	var xhr = new XMLHttpRequest()
	xhr.open('GET', url)
	xhr.responseType = 'blob'
	xhr.onload = function() {
		saveAs(xhr.response, name, opts)
	}
	xhr.onerror = function() {
		console.error('could not download file')
	}
	xhr.send()
}

function corsEnabled(url) {
	var xhr = new XMLHttpRequest()
	// use sync to avoid popup blocker
	xhr.open('HEAD', url, false)
	try {
		xhr.send()
	} catch (e) {}
	return xhr.status >= 200 && xhr.status <= 299
}

// `a.click()` doesn't work for all browsers (#465)
function click(node) {
	try {
		node.dispatchEvent(new MouseEvent('click'))
	} catch (e) {
		var evt = document.createEvent('MouseEvents')
		evt.initMouseEvent('click', true, true, window, 0, 0, 0, 80,
			20, false, false, false, false, 0, null)
		node.dispatchEvent(evt)
	}
}

// Detect WebView inside a native macOS app by ruling out all browsers
// We just need to check for 'Safari' because all other browsers (besides Firefox) include that too
// https://www.whatismybrowser.com/guides/the-latest-user-agent/macos
var isMacOSWebView = _global.navigator && /Macintosh/.test(navigator.userAgent) && /AppleWebKit/.test(navigator
	.userAgent) && !/Safari/.test(navigator.userAgent)

var saveAs = _global.saveAs || (
	// probably in some web worker
	(typeof window !== 'object' || window !== _global) ?
	function saveAs() {
		/* noop */ }

	// Use download attribute first if possible (#193 Lumia mobile) unless this is a macOS WebView
	:
	('download' in HTMLAnchorElement.prototype && !isMacOSWebView) ?
	function saveAs(blob, name, opts) {
		var URL = _global.URL || _global.webkitURL
		// Namespace is used to prevent conflict w/ Chrome Poper Blocker extension (Issue #561)
		var a = document.createElementNS('http://www.w3.org/1999/xhtml', 'a')
		name = name || blob.name || 'download'

		a.download = name
		a.rel = 'noopener' // tabnabbing

		// TODO: detect chrome extensions & packaged apps
		// a.target = '_blank'

		if (typeof blob === 'string') {
			// Support regular links
			a.href = blob
			if (a.origin !== location.origin) {
				corsEnabled(a.href) ?
					download(blob, name, opts) :
					click(a, a.target = '_blank')
			} else {
				click(a)
			}
		} else {
			// Support blobs
			a.href = URL.createObjectURL(blob)
			setTimeout(function() {
				URL.revokeObjectURL(a.href)
			}, 4E4) // 40s
			setTimeout(function() {
				click(a)
			}, 0)
		}
	}

	// Use msSaveOrOpenBlob as a second approach
	:
	'msSaveOrOpenBlob' in navigator ?
	function saveAs(blob, name, opts) {
		name = name || blob.name || 'download'

		if (typeof blob === 'string') {
			if (corsEnabled(blob)) {
				download(blob, name, opts)
			} else {
				var a = document.createElement('a')
				a.href = blob
				a.target = '_blank'
				setTimeout(function() {
					click(a)
				})
			}
		} else {
			navigator.msSaveOrOpenBlob(bom(blob, opts), name)
		}
	}

	// Fallback to using FileReader and a popup
	:
	function saveAs(blob, name, opts, popup) {
		// Open a popup immediately do go around popup blocker
		// Mostly only available on user interaction and the fileReader is async so...
		popup = popup || open('', '_blank')
		if (popup) {
			popup.document.title =
				popup.document.body.innerText = 'downloading...'
		}

		if (typeof blob === 'string') return download(blob, name, opts)

		var force = blob.type === 'application/octet-stream'
		var isSafari = /constructor/i.test(_global.HTMLElement) || _global.safari
		var isChromeIOS = /CriOS\/[\d]+/.test(navigator.userAgent)

		if ((isChromeIOS || (force && isSafari) || isMacOSWebView) && typeof FileReader !== 'undefined') {
			// Safari doesn't allow downloading of blob URLs
			var reader = new FileReader()
			reader.onloadend = function() {
				var url = reader.result
				url = isChromeIOS ? url : url.replace(/^data:[^;]*;/, 'data:attachment/file;')
				if (popup) popup.location.href = url
				else location = url
				popup = null // reverse-tabnabbing #460
			}
			reader.readAsDataURL(blob)
		} else {
			var URL = _global.URL || _global.webkitURL
			var url = URL.createObjectURL(blob)
			if (popup) popup.location = url
			else location.href = url
			popup = null // reverse-tabnabbing #460
			setTimeout(function() {
				URL.revokeObjectURL(url)
			}, 4E4) // 40s
		}
	}
)

_global.saveAs = saveAs.saveAs = saveAs

if (typeof module !== 'undefined') {
	module.exports = saveAs;
}