angularjs ng-show with promise expression
I\'m using ng-show with an expression that resolves to a promise that resolves to a boolean. When I do this I get the 10 digest iterations overflow.
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Plunker: http://plnkr.co/edit/NvjP5qHafhyIWXXotBej?p=preview
This works as I think you intended it to.
$q.when()returns a promise object, song-showis not getting a boolean value; it's getting a promise object.Updated template:
<body ng-controller="MainCtrl"> <p ng-show="returnsABoolean()">non promise</p> <p ng-show="returnsAPromiseThatResolvesToABoolean">promise</p> </body>Updated Ctrl:
$scope.returnsABoolean = ()-> true promise = $q.when(false) promise.then((val) -> $scope.returnsAPromiseThatResolvesToABoolean = val)讨论(0) -
AngularJS resolves the promise for template binding automatically. However, you should use the promise in
ng-initto prevent the digest cycle from returning a new promise every tick.<p ng-init="v=returnsAPromiseThatResolvesToABoolean()" ng-show="v">promise</p>讨论(0) -
If you check out the sources here you 'll see that the promise is resolved in
nextTick, so the$scopeonly changes the next time angular makes a$digestcycle. But your function returns a new promise on every$digestcycle, never actually getting the resolved value of the previous promise.It's an old problem discussed here also.
You can overcome this issue by keeping a "persistent" reference to your promise outside the function as I did here.
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