783d2f332b
Add directive for exposing expressions which should be evaluated for the browser's onbeforeunload event, to prevent user-initiated navigation from causing a loss of unsaved changes. WTD-1035.
68 lines
2.2 KiB
JavaScript
68 lines
2.2 KiB
JavaScript
/*global define*/
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define(
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[],
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function () {
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"use strict";
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/**
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* Defines the `mct-before-unload` directive. The expression bound
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* to this attribute will be evaluated during page navigation events
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* and, if it returns a truthy value, will be used to populate a
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* prompt to the user to confirm this navigation.
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* @constructor
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* @param $window the window
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*/
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function MCTBeforeUnload($window) {
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var unloads = [],
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oldBeforeUnload = $window.onbeforeunload;
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// Run all unload functions, returning the first returns truthily.
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function checkUnloads() {
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var result;
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unloads.forEach(function (unload) {
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result = result || unload();
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});
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return result;
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}
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// Link function for an mct-before-unload directive usage
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function link(scope, element, attrs) {
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// Invoke the
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function unload() {
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return scope.$eval(attrs.mctBeforeUnload);
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}
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// Stop using this unload expression
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function removeUnload() {
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unloads = unloads.filter(function (callback) {
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return callback !== unload;
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});
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if (unloads.length === 0) {
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$window.onbeforeunload = oldBeforeUnload;
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}
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}
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// Include this instance of the directive's unload function
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unloads.push(unload);
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// If this is the first active instance of this directive,
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// register as the window's beforeunload handler
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$window.onbeforeunload = checkUnloads;
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// Remove it when the scope is destroyed
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scope.$on("$destroy", removeUnload);
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}
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return {
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// Applicable as an attribute
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restrict: "A",
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// Link with the provided function
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link: link
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};
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}
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return MCTBeforeUnload;
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}
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); |