angularjsHow can I use AngularJS to watch an array for changes?
AngularJS provides a $watch
function for watching an array for changes. This function takes two arguments: the array to watch and a callback function that will be called when the array changes.
var arr = [1, 2, 3];
$scope.$watch(arr, function (newArr, oldArr) {
console.log('Array changed from', oldArr, 'to', newArr);
});
arr.push(4);
// Output: Array changed from [1, 2, 3] to [1, 2, 3, 4]
The $watch
function takes two arguments:
- The array to watch (
arr
in the example above). - A callback function that will be called when the array changes (
function (newArr, oldArr)
in the example above). The callback function takes two arguments: the new array (newArr
) and the old array (oldArr
).
In the example code above, the $watch
function is used to watch the arr
array. When the arr.push(4)
statement is executed, the callback function is called and the output Array changed from [1, 2, 3] to [1, 2, 3, 4]
is displayed.
For more information on the $watch
function, see the AngularJS documentation.
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