Created
May 3, 2014 07:44
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Code from angular - digest loop presentation
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| function Scope() { | |
| this.$$watchers = []; | |
| this.$$lastDirtyWatch = null; | |
| } | |
| Scope.prototype.$$areEqual = function(newValue, oldValue, valueEq) { | |
| if (valueEq) { | |
| return _.isEqual(newValue, oldValue); | |
| } else { | |
| return newValue === oldValue || | |
| (typeof newValue === 'number' && typeof oldValue === 'number' && | |
| isNaN(newValue) && isNaN(oldValue)); | |
| } | |
| }; | |
| Scope.prototype.$watch = function(watchFn, listenerFn, valueEq) { | |
| var self = this; | |
| var watcher = { | |
| watchFn: watchFn, | |
| listenerFn: listenerFn || function() {}, | |
| valueEq: !!valueEq | |
| }; | |
| self.$$watchers.push(watcher); | |
| return function() { | |
| var index = self.$$watchers.indexOf(watcher); | |
| if (index >= 0) { | |
| self.$$watchers.splice(index, 1); | |
| } | |
| } | |
| }; | |
| Scope.prototype.$$digestOnce = function() { | |
| var self = this; | |
| var dirty = false; | |
| this.$$watchers.every(function(watch) { | |
| var newValue = watch.watchFn(self); | |
| var oldValue = watch.last; | |
| if (!self.$$areEqual(newValue, oldValue, watch.valueEq)) { | |
| watch.last = (watch.valueEq ? _.cloneDeep(newValue) : newValue); | |
| watch.listenerFn(newValue, oldValue, self); | |
| dirty = true; | |
| self.$$lastDirtyWatch = watch; | |
| } else if (self.$$lastDirtyWatch === watch) { | |
| return false; | |
| } | |
| return true; | |
| }); | |
| Scope.prototype.$digest = function() { | |
| var ttl = 10; | |
| var dirty; | |
| this.$$lastDirtyWatch = null; | |
| do { | |
| dirty = this.$$digestOnce(); | |
| if (dirty && !(ttl--)) { | |
| throw "10 digest iterations reached"; | |
| } | |
| } while (dirty); | |
| }; | |
| Scope.prototype.$eval = function(expr, locals) { | |
| return expr(this, locals); | |
| }; | |
| Scope.prototype.$apply = function(expr) { | |
| try { | |
| return this.$eval(expr); | |
| } finally { | |
| this.$digest(); | |
| } | |
| }; |
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