AngularJS $watch vs $watchCollection：这是更好的性能？

发布时间：2020-12-17 08:31:52 所属栏目：安全来源：网络整理

导读：对于观察对象范围变量，是$ scope。$ watch with objectEquality设置为true OR $ scope。$ watchCollection更好？对于一个$ scope对象变量(如15个属性，一些嵌套的2级深度)用视图中的输入元素和ng-model更新，$ scope有多糟糕$ watch with objectEquality设

对于观察对象范围变量，是$ scope。$ watch with objectEquality设置为true OR $ scope。$ watchCollection更好？

对于一个$ scope对象变量(如15个属性，一些嵌套的2级深度)用视图中的输入元素和ng-model更新，$ scope有多糟糕$ watch with objectEquality设置为true？这是一件值得避免的事吗？

是$ watchCollection更好的解决方案吗？

我正在寻找容易的胜利，以提高我的AngularJS应用程序的性能(我仍然坚持在v1.2.2)。

// ctrl scope var
  $scope.filters = {
    name: '',info: {test: '',foo: '',bar: ''},yep: ''
    // etc ...
  }

  // ctrl watch ?
  $scope.$watch('filters',function(newVal,oldVal) {
    if(newVal !== oldVal) {
      // call with updated filters
    }
  },true);

  // or ctrl watch collection ?
  $scope.$watchCollection('filters',oldVal) {
    if(newVal !== oldVal) {
      // call with updated filters
    }
  });

  // view input with ng-model
  <input type="text" ng-model="filters.name" />
  <input type="text" ng-model="filters.info.test" />
  <input type="text" ng-model="filters.yep" />
  // etc ...

The $watchCollection() function is a sort-of mid-ground between the
two $watch() configurations above. It’s more in-depth than the
vanilla $watch() function; but,it’s not nearly as expensive as the
deep-equality $watch() function. Like the $watch() function,the
$watchCollection() works by comparing physical object references;
however,unlike the $watch() function,the $watchCollection() goes
one-level deep and performs an additional,shallow reference check of
the top level items in the collection.

see this explanation

（编辑：李大同）

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