範圍功能和過濾器

AngularJS 具有摘要迴圈，每次執行摘要週期時都會在檢視和過濾器中執行所有功能。每當更新模型時都會執行摘要迴圈，它會降低你的應用程式速度（在頁面載入之前可以多次點選過濾器）。

你應該避免這個：

<div ng-controller="bigCalulations as calc">
  <p>{{calc.calculateMe()}}</p>
  <p>{{calc.data | heavyFilter}}</p>
</div>

更好的方法

<div ng-controller="bigCalulations as calc">
  <p>{{calc.preCalculatedValue}}</p>
  <p>{{calc.data | lightFilter}}</p>
</div>

控制器樣本的位置是：

.controller("bigCalulations", function(valueService) {
  // bad, because this is called in every digest loop
  this.calculateMe = function() {
    var t = 0;
    for(i = 0; i < 1000; i++) {
      t = t + i;
    }
    return t;
  }
  //good, because it is executed just once and logic is separated in service to    keep the controller light
  this.preCalulatedValue = valueService.caluclateSumm(); // returns 499500
});