diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/Angular.js | 3 | ||||
| -rw-r--r-- | src/directives.js | 8 | ||||
| -rw-r--r-- | src/service/scope.js | 20 |
3 files changed, 24 insertions, 7 deletions
diff --git a/src/Angular.js b/src/Angular.js index 127be95d..e5f35bba 100644 --- a/src/Angular.js +++ b/src/Angular.js @@ -624,6 +624,7 @@ function copy(source, destination){ * * * Both objects or values pass `===` comparison. * * Both objects or values are of the same type and all of their properties pass `===` comparison. + * * Both values are NaN. (In JavasScript, NaN == NaN => false. But we consider two NaN as equal) * * During a property comparision, properties of `function` type and properties with names * that begin with `$` are ignored. @@ -634,11 +635,11 @@ function copy(source, destination){ * @param {*} o1 Object or value to compare. * @param {*} o2 Object or value to compare. * @returns {boolean} True if arguments are equal. - * */ function equals(o1, o2) { if (o1 === o2) return true; if (o1 === null || o2 === null) return false; + if (o1 !== o1 && o2 !== o2) return true; // NaN === NaN var t1 = typeof o1, t2 = typeof o2, length, key, keySet; if (t1 == t2 && t1 == 'object') { if (isArray(o1)) { diff --git a/src/directives.js b/src/directives.js index da540df5..41fbac16 100644 --- a/src/directives.js +++ b/src/directives.js @@ -576,7 +576,9 @@ function ngClass(selector) { return function(element) { this.$watch(expression, function(scope, newVal, oldVal) { if (selector(scope.$index)) { - if (oldVal) element.removeClass(isArray(oldVal) ? oldVal.join(' ') : oldVal); + if (oldVal && (newVal !== oldVal)) { + element.removeClass(isArray(oldVal) ? oldVal.join(' ') : oldVal); + } if (newVal) element.addClass(isArray(newVal) ? newVal.join(' ') : newVal); } }); @@ -823,7 +825,9 @@ angularDirective("ng:hide", function(expression, element){ angularDirective("ng:style", function(expression, element) { return function(element) { this.$watch(expression, function(scope, newStyles, oldStyles) { - if (oldStyles) forEach(oldStyles, function(val, style) { element.css(style, '');}); + if (oldStyles && (newStyles !== oldStyles)) { + forEach(oldStyles, function(val, style) { element.css(style, '');}); + } if (newStyles) element.css(newStyles); }); }; diff --git a/src/service/scope.js b/src/service/scope.js index df969cfc..cbda4495 100644 --- a/src/service/scope.js +++ b/src/service/scope.js @@ -187,7 +187,8 @@ function $RootScopeProvider(){ * reruns when it detects changes the `watchExpression` can execute multiple times per * {@link angular.module.ng.$rootScope.Scope#$digest $digest()} and should be idempotent.) * - The `listener` is called only when the value from the current `watchExpression` and the - * previous call to `watchExpression' are not equal. The inequality is determined according to + * previous call to `watchExpression' are not equal (with the exception of the initial run + * see below). The inequality is determined according to * {@link angular.equals} function. To save the value of the object for later comparison * {@link angular.copy} function is used. It also means that watching complex options will * have adverse memory and performance implications. @@ -201,6 +202,13 @@ function $RootScopeProvider(){ * can execute multiple times per {@link angular.module.ng.$rootScope.Scope#$digest $digest} cycle when a change is * detected, be prepared for multiple calls to your listener.) * + * After a watcher is registered with the scope, the `listener` fn is called asynchronously + * (via {@link angular.module.ng.$rootScope.Scope#$evalAsync $evalAsync}) to initialize the + * watcher. In rare cases, this is undesirable because the listener is called when the result + * of `watchExpression` didn't change. To detect this scenario within the `listener` fn, you + * can compare the `newVal` and `oldVal`. If these two values are identical (`===`) then the + * listener was called due to initialization. + * * * # Example <pre> @@ -244,7 +252,7 @@ function $RootScopeProvider(){ array = scope.$$watchers, watcher = { fn: listenFn, - last: Number.NaN, // NaN !== NaN. We used this to force $watch to fire on first run. + last: initWatchVal, get: get, exp: watchExp }; @@ -345,7 +353,7 @@ function $RootScopeProvider(){ if ((value = watch.get(current)) !== (last = watch.last) && !equals(value, last)) { dirty = true; watch.last = copy(value); - watch.fn(current, value, last); + watch.fn(current, value, ((last === initWatchVal) ? value : last)); if (ttl < 5) { if (!watchLog[4-ttl]) watchLog[4-ttl] = []; if (isFunction(watch.exp)) { @@ -669,6 +677,10 @@ function $RootScopeProvider(){ return fn; } - + /** + * function used as an initial value for watchers. + * because it's uniqueue we can easily tell it apart from other values + */ + function initWatchVal() {} }]; } |