javascript - AngularJs:双重检查 ng-show

Question

为什么像 ng-show(或其他)这样的指令中的任何表达式的检查都是重复的？我做了简单的jsfiddle示例http://jsfiddle.net/fA5YX/ 。在浏览器控制台中查看。

<div ng-app ng-controller="ctrl" ng-show="test()">shown</div>
<script>
function ctrl($scope) {
    $scope.test = function() {
        console.log('check');
        return true;
    }
}
</script>

如何让它停止？我只需要一张支票。

Answer 1

可能链接到Controller function getting called twice using ng-show - 引用:

At each digest cycle, for every watch, AngularJS evaluates the associated expression to see if there's any change and if there is, invoking the listener (in the case of ng-show/ng-hide, the listener will show or hide the element based on the value returned by ready()).