FileSaver.js

/* FileSaver.js
 * A saveAs() FileSaver implementation.
 * 1.3.8
 * 2018-03-22 14:03:47
 *
 * By Eli Grey, https://eligrey.com
 * License: MIT
 *   See https://github.com/eligrey/FileSaver.js/blob/master/LICENSE.md
 */

/*global self */
/*jslint bitwise: true, indent: 4, laxbreak: true, laxcomma: true, smarttabs: true, plusplus: true */

/*! @source http://purl.eligrey.com/github/FileSaver.js/blob/master/src/FileSaver.js */

function Make_saveAs(view) {
	"use strict";
	// IE <10 is explicitly unsupported
	if (typeof view === "undefined" || typeof navigator !== "undefined" && /MSIE [1-9]\./.test(navigator.userAgent)) {
		return;
	}
	var
		doc = view.document
		// only get URL when necessary in case Blob.js hasn't overridden it yet
		,
		get_URL = function () {
			return view.URL || view.webkitURL || view;
		},
		save_link = doc.createElementNS("http://www.w3.org/1999/xhtml", "a"),
		can_use_save_link = "download" in save_link,
		click = function (node) {
			var event = new MouseEvent("click");
			node.dispatchEvent(event);
		},
		is_safari = /constructor/i.test(view.HTMLElement) || view.safari,
		is_chrome_ios = /CriOS\/[\d]+/.test(navigator.userAgent),
		setImmediate = view.setImmediate || view.setTimeout,
		throw_outside = function (ex) {
			setImmediate(function () {
				throw ex;
			}, 0);
		},
		force_saveable_type = "application/octet-stream"
		// the Blob API is fundamentally broken as there is no "downloadfinished" event to subscribe to
		,
		arbitrary_revoke_timeout = 1000 * 40 // in ms
		,
		revoke = function (file) {
			var revoker = function () {
				if (typeof file === "string") { // file is an object URL
					get_URL().revokeObjectURL(file);
				} else { // file is a File
					file.remove();
				}
			};
			setTimeout(revoker, arbitrary_revoke_timeout);
		},
		dispatch = function (filesaver, event_types, event) {
			event_types = [].concat(event_types);
			var i = event_types.length;
			while (i--) {
				var listener = filesaver["on" + event_types[i]];
				if (typeof listener === "function") {
					try {
						listener.call(filesaver, event || filesaver);
					} catch (ex) {
						throw_outside(ex);
					}
				}
			}
		},
		auto_bom = function (blob) {
			// 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 (/^\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;
		},
		FileSaver = function (blob, name, no_auto_bom) {
			if (!no_auto_bom) {
				blob = auto_bom(blob);
			}
			// First try a.download, then web filesystem, then object URLs
			var
				filesaver = this,
				type = blob.type,
				force = type === force_saveable_type,
				object_url, dispatch_all = function () {
					dispatch(filesaver, "writestart progress write writeend".split(" "));
				}
				// on any filesys errors revert to saving with object URLs
				,
				fs_error = function () {
					if ((is_chrome_ios || (force && is_safari)) && view.FileReader) {
						// Safari doesn't allow downloading of blob urls
						var reader = new FileReader();
						reader.onloadend = function () {
							var url = is_chrome_ios ? reader.result : reader.result.replace(/^data:[^;]*;/, 'data:attachment/file;');
							var popup = view.open(url, '_blank');
							if (!popup) view.location.href = url;
							url = undefined; // release reference before dispatching
							filesaver.readyState = filesaver.DONE;
							dispatch_all();
						};
						reader.readAsDataURL(blob);
						filesaver.readyState = filesaver.INIT;
						return;
					}
					// don't create more object URLs than needed
					if (!object_url) {
						object_url = get_URL().createObjectURL(blob);
					}
					if (force) {
						view.location.href = object_url;
					} else {
						var opened = view.open(object_url, "_blank");
						if (!opened) {
							// Apple does not allow window.open, see https://developer.apple.com/library/safari/documentation/Tools/Conceptual/SafariExtensionGuide/WorkingwithWindowsandTabs/WorkingwithWindowsandTabs.html
							view.location.href = object_url;
						}
					}
					filesaver.readyState = filesaver.DONE;
					dispatch_all();
					revoke(object_url);
				};
			filesaver.readyState = filesaver.INIT;

			if (can_use_save_link) {
				object_url = get_URL().createObjectURL(blob);
				setImmediate(function () {
					save_link.href = object_url;
					save_link.download = name;
					click(save_link);
					dispatch_all();
					revoke(object_url);
					filesaver.readyState = filesaver.DONE;
				}, 0);
				return;
			}

			fs_error();
		},
		FS_proto = FileSaver.prototype,
		saveAs = function (blob, name, no_auto_bom) {
			return new FileSaver(blob, name || blob.name || "download", no_auto_bom);
		};

	// IE 10+ (native saveAs)
	if (typeof navigator !== "undefined" && navigator.msSaveOrOpenBlob) {
		return function (blob, name, no_auto_bom) {
			name = name || blob.name || "download";

			if (!no_auto_bom) {
				blob = auto_bom(blob);
			}
			return navigator.msSaveOrOpenBlob(blob, name);
		};
	}

	// todo: detect chrome extensions & packaged apps
	//save_link.target = "_blank";

	FS_proto.abort = function () {};
	FS_proto.readyState = FS_proto.INIT = 0;
	FS_proto.WRITING = 1;
	FS_proto.DONE = 2;

	FS_proto.error =
		FS_proto.onwritestart =
		FS_proto.onprogress =
		FS_proto.onwrite =
		FS_proto.onabort =
		FS_proto.onerror =
		FS_proto.onwriteend =
		null;

	return saveAs;
}