javascript - limitTo : not working in AngularJS

Question

AngularJS

userData.success(function (userdataobject) {
                  $scope.catadata = userdataobject;
                $scope.quantity = 1;
            });
            userData.success(function (userdataobject) {
                  $scope.catadata1 = userdataobject;
                $scope.quantity1 = 1;
            });

AngularJS 2 种不同的循环代码

循环 1

 <div ng-repeat="cat in catadata | limitTo:quantity | filter: {TopCategoryID : 11}">

循环 2

<div ng-repeat="cat1 in catadata1 | limitTo:quantity1 | filter: {TopCategoryID : 12}">

limitTo:quantity 有效，但 limitTo:quantity1 无效

Answer 1

TLDR:您必须将 limitTo 过滤器移至末尾:

<div ng-repeat="cat1 in catadata1 | filter: {TopCategoryID : 12} | limitTo:quantity1">

limitTo filter将创建一个具有所需长度的新数组，然后将应用您的过滤器，考虑一下:

var catadata1 = [
    {TopCategoryID: 13, ...},
    {TopCategoryID: 42, ...},
    {TopCategoryID: 12, ...},
    ...
];
// When we apply the limitTo, this is what's happening:
var limitTo = catadata1.slice(0, 1); // Keep the first item
// And when we apply the filter we only filter on the limitTo array:
var filter = limitTo.filter(matchItem({TopCategoryID : 12}));

另一种查看方式是:

var a = [0, 1, 2]; // Initial Array
var b = [0] // limitTo: 1
var c = [] // filter: 2

同时:

var a = [0, 1, 2]; // Initial Array
var b = [0] // limitTo: 1
var c = [0] // filter: 0

这就是您的代码中发生的情况，只是使用了另一个过滤器。