1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
|
'use strict';
/**
* @ngdoc directive
* @name ngIf
* @restrict A
*
* @description
* The `ngIf` directive removes or recreates a portion of the DOM tree based on an
* {expression}. If the expression assigned to `ngIf` evaluates to a false
* value then the element is removed from the DOM, otherwise a clone of the
* element is reinserted into the DOM.
*
* `ngIf` differs from `ngShow` and `ngHide` in that `ngIf` completely removes and recreates the
* element in the DOM rather than changing its visibility via the `display` css property. A common
* case when this difference is significant is when using css selectors that rely on an element's
* position within the DOM, such as the `:first-child` or `:last-child` pseudo-classes.
*
* Note that when an element is removed using `ngIf` its scope is destroyed and a new scope
* is created when the element is restored. The scope created within `ngIf` inherits from
* its parent scope using
* [prototypal inheritance](https://github.com/angular/angular.js/wiki/The-Nuances-of-Scope-Prototypal-Inheritance).
* An important implication of this is if `ngModel` is used within `ngIf` to bind to
* a javascript primitive defined in the parent scope. In this case any modifications made to the
* variable within the child scope will override (hide) the value in the parent scope.
*
* Also, `ngIf` recreates elements using their compiled state. An example of this behavior
* is if an element's class attribute is directly modified after it's compiled, using something like
* jQuery's `.addClass()` method, and the element is later removed. When `ngIf` recreates the element
* the added class will be lost because the original compiled state is used to regenerate the element.
*
* Additionally, you can provide animations via the `ngAnimate` module to animate the `enter`
* and `leave` effects.
*
* @animations
* enter - happens just after the ngIf contents change and a new DOM element is created and injected into the ngIf container
* leave - happens just before the ngIf contents are removed from the DOM
*
* @element ANY
* @scope
* @priority 600
* @param {expression} ngIf If the {@link guide/expression expression} is falsy then
* the element is removed from the DOM tree. If it is truthy a copy of the compiled
* element is added to the DOM tree.
*
* @example
<example module="ngAnimate" deps="angular-animate.js" animations="true">
<file name="index.html">
Click me: <input type="checkbox" ng-model="checked" ng-init="checked=true" /><br/>
Show when checked:
<span ng-if="checked" class="animate-if">
I'm removed when the checkbox is unchecked.
</span>
</file>
<file name="animations.css">
.animate-if {
background:white;
border:1px solid black;
padding:10px;
}
.animate-if.ng-enter, .animate-if.ng-leave {
-webkit-transition:all cubic-bezier(0.250, 0.460, 0.450, 0.940) 0.5s;
transition:all cubic-bezier(0.250, 0.460, 0.450, 0.940) 0.5s;
}
.animate-if.ng-enter,
.animate-if.ng-leave.ng-leave-active {
opacity:0;
}
.animate-if.ng-leave,
.animate-if.ng-enter.ng-enter-active {
opacity:1;
}
</file>
</example>
*/
var ngIfDirective = ['$animate', function($animate) {
return {
transclude: 'element',
priority: 600,
terminal: true,
restrict: 'A',
$$tlb: true,
link: function ($scope, $element, $attr, ctrl, $transclude) {
var block, childScope, previousElements;
$scope.$watch($attr.ngIf, function ngIfWatchAction(value) {
if (toBoolean(value)) {
if (!childScope) {
childScope = $scope.$new();
$transclude(childScope, function (clone) {
clone[clone.length++] = document.createComment(' end ngIf: ' + $attr.ngIf + ' ');
// Note: We only need the first/last node of the cloned nodes.
// However, we need to keep the reference to the jqlite wrapper as it might be changed later
// by a directive with templateUrl when it's template arrives.
block = {
clone: clone
};
$animate.enter(clone, $element.parent(), $element);
});
}
} else {
if(previousElements) {
previousElements.remove();
previousElements = null;
}
if(childScope) {
childScope.$destroy();
childScope = null;
}
if(block) {
previousElements = getBlockElements(block.clone);
$animate.leave(previousElements, function() {
previousElements = null;
});
block = null;
}
}
});
}
};
}];
|
