我是角度js的新手，我试图使用ng-repeat获得独特的值。我浏览了很多网站，其中一个是enter link description here
我只从stackoverflow获得。 var app = angular.module（＆＃39; app＆＃39;，[]）;
app.filter('unique', function() {
return function(collection, keyname) {
var output = [],
keys = [];
angular.forEach(collection, function(item) {
var key = item[keyname];
if(keys.indexOf(key) === -1) {
keys.push(key);
output.push(item);
}
});
return output;
};
});
app.controller('MyCtrl', function ($scope) {
$scope.items = [
{ id : 1,column : "col1", comment : "col1-label1",
text1 : "col1-label1-text1",
checked: false,
},
{
id : 2,
column : "col1",
comment : "col1-label2",
text1 : "col1-label2-text1",
checked: false,
},
{
id : 3,
column : "col2",
comment : "col2-label1",
text1 : "col2-label1-text1",
checked: false,
},
{
id : 4,
column : "col2",
comment : "col2-label2",
text1 : "col2-label2-text1",
checked: false,
},
{
id : 5,
column : "col3",
comment : "col3-label1",
text1 : "col3-label1-text1",
checked: false,
},
{
id : 6,
column : "col3",
comment : "col3-label2",
text1 : "col3-label2-text1",
checked: false,
},
{
id : 7,
column : "col4",
comment : "col4-label1",
text1 : "col4-label1-text1",
checked: false,
},
{
id : 8,
column : "col4",
comment : "col4-label2",
text1 : "col4-label2-text1",
checked: false,
}
];
});
但我有一个问题需要理解，我已经花了好几个小时但仍然无法理解。
**angular.forEach(collection, function(item) {
var key = item[keyname];**
In forEach method in the function we pass value , index and then the object itself that we are iterating over, In the above example we are only passing the value as "item" , then in the next line we are using as object/array. I am really confused, what is it? what are they trrying to do