How to $watch changes on models created by ng-repeat?

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 6  1972

Consider this Plnkr for example. I don\'t know how many members of fooCollection will be created beforehand. So I don\'t know how many bar models a

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暗喜

2020-12-08 01:07

Try to do this

 <div ng-repeat="foo in fooCollection" ng-click="select(foo)">Tell me your ame:
        <input ng-model="foo.bar" ng-change="fooChanged(foo)">
        <br />Hello, my name is {{foo.bar}}</div>
        <button ng-click="fooCollection.push({})">Add a Namer</button>
 </div>

There is the code in Directive/Controller

 $scope.selectedfoo = {};
 $scope.select = (foo) => {
    $scope.selectedfoo = foo;
 }

 $scope.$watch('selectedfoo ', (newVal, oldVal) => {
  if (newVal) {

  }
 },true)

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清歌不尽

2020-12-08 01:14

If you have your collection populated, you can place a watch on each item of the ng-repeat:

html

<div ng-repeat="item in items">
   {{ item.itemField }}
</div>

for (var i = 0; i < $scope.items.length; i++) {
   $scope.$watch('items[' + i + ']', function (newValue, oldValue) {
      console.log(newValue.itemField + ":::" + oldValue.itemField);
   }, true);
}

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别跟我提以往

2020-12-08 01:19

Since I didn't want another controller I ended up using ng-change instead.

Simple jsFiddle: https://jsfiddle.net/maistho/z0xazw5n/

Relevant HTML:

<body ng-app="testApp" ng-controller="testCtrl">
    <div ng-repeat="foo in fooCollection">Tell me your name:
        <input ng-model="foo.bar" ng-change="fooChanged(foo)">
        <br />Hello, my name is {{foo.bar}}</div>
    <button ng-click="fooCollection.push({})">Add a Namer</button>
</body>

Relevant JS:

angular.module('testApp', [])
    .controller('testCtrl', function ($scope) {
    $scope.fooCollection = [];

    $scope.fooChanged = function (foo) {
        console.log('foo.bar changed, new value of foo.bar is: ', foo.bar);
    };
});

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抹茶落季

2020-12-08 01:23
You can pass true as third argument into $watch
```
$scope.$watch('something', function() { doSomething(); }, true);
```
https://docs.angularjs.org/api/ng/type/$rootScope.Scope
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南笙

2020-12-08 01:34

Create individual list-item controllers: demo on Plnkr

js

angular
  .module('testApp', [])
  .controller('testCtrl', function ($scope) {
    $scope.fooCollection = [];
  })
  .controller('fooCtrl', function ($scope) {
    $scope.$watch('foo.bar', function (newValue, oldValue) {
      console.log('watch fired, new value: ' + newValue);
    });
  });

HTML

<html ng-app="testApp">
  <body ng-controller="testCtrl">
    <div ng-repeat="(fooKey, foo) in fooCollection" ng-controller="fooCtrl">
      Tell me your name: <input ng-model="foo.bar" ng-change="doSomething()">
      <br />
      Hello, my name is {{ foo.bar }}
    </div>
    <button ng-click="fooCollection.push([])">Add a Namer</button>
  </body>
</html>

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隐瞒了意图╮

2020-12-08 01:34

You can also create a custom directive that will tell your main controller for the changes

YourModule.directive("batchWatch",[function(){
return {
    scope:"=",
    replace:false,
    link:function($scope,$element,$attrs,Controller){
        $scope.$watch('h',function(newVal,oldVal){
            if(newVal !== oldVal){
              Controller.updateChange(newVal,oldVal,$scope.$parent.$index);
            }

        },true);

    },
    controller:"yourController"
};
}]);

assume your markup is like this

<ul>
  <li ng-repeat="h in complicatedArrayOfObjects">
      <input type="text" ng-model="someModel" batch-watch="$index" />
  </li>
</ul>

and this is your controller

YourModule.controller("yourController",[$scope,function($scope){
    this.updateChange = function(newVal,oldVal,indexChanged){
      console.log("Details about the change");
    }
}]);

You can also play around the value provided by the directive link function which sits on first 3 arguments, scope,element and attr.

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