How can i get a reversed array in angular? i'm trying to use orderBy filter, but it needs a predicate(e.g. 'name') to sort:
<tr ng-repeat="friend in friends | orderBy:'name':true">
<td>{{friend.name}}</td>
<td>{{friend.phone}}</td>
<td>{{friend.age}}</td>
<tr>
Is there a way to reverse original array, without sorting. like that:
<tr ng-repeat="friend in friends | orderBy:'':true">
<td>{{friend.name}}</td>
<td>{{friend.phone}}</td>
<td>{{friend.age}}</td>
<tr>
This question is related to
javascript
arrays
angularjs
reverse
angularjs-ng-repeat
I would suggest using a custom filter such as this:
app.filter('reverse', function() {
return function(items) {
return items.slice().reverse();
};
});
Which can then be used like:
<div ng-repeat="friend in friends | reverse">{{friend.name}}</div>
See it working here: Plunker Demonstration
This filter can be customized to fit your needs as seen fit. I have provided other examples in the demonstration. Some options include checking that the variable is an array before performing the reverse, or making it more lenient to allow the reversal of more things such as strings.
Useful tip:
You can reverse you're array with vanilla Js: yourarray .reverse()
Caution: reverse is destructive, so it will change youre array, not only the variable.
You can also use .reverse(). It's a native array function
<div ng-repeat="friend in friends.reverse()">{{friend.name}}</div>
Simple solution:- (no need to make any methods)
ng-repeat = "friend in friends | orderBy: reverse:true"
I would sugest using array native reverse method is always better choice over creating filter or using $index.
<div ng-repeat="friend in friends.reverse()">{{friend.name}}</div>
When using MVC in .NET with Angular you can always use OrderByDecending() when doing your db query like this:
var reversedList = dbContext.GetAll().OrderByDecending(x => x.Id).ToList();
Then on the Angular side, it will already be reversed in some browsers (IE). When supporting Chrome and FF, you would then need to add orderBy:
<tr ng-repeat="item in items | orderBy:'-Id'">
In this example, you'd be sorting in descending order on the .Id property. If you're using paging, this gets more complicated because only the first page would be sorted. You'd need to handle this via a .js filter file for your controller, or in some other way.
This is what i used:
<alert ng-repeat="alert in alerts.slice().reverse()" type="alert.type" close="alerts.splice(index, 1)">{{$index + 1}}: {{alert.msg}}</alert>
Update:
My answer was OK for old version of Angular. Now, you should be using
ng-repeat="friend in friends | orderBy:'-'"
or
ng-repeat="friend in friends | orderBy:'+':true"
if you are using 1.3.x, you can use the following
{{ orderBy_expression | orderBy : expression : reverse}}
Example List books by published date in descending order
<div ng-repeat="book in books|orderBy:'publishedDate':true">
I found something like this, but instead of array i use objects.
Here is my solution for objects:
Add custom filter:
app.filter('orderObjectBy', function() {
return function(items, field, reverse){
var strRef = function (object, reference) {
function arr_deref(o, ref, i) {
return !ref ? o : (o[ref.slice(0, i ? -1 : ref.length)]);
}
function dot_deref(o, ref) {
return !ref ? o : ref.split('[').reduce(arr_deref, o);
}
return reference.split('.').reduce(dot_deref, object);
};
var filtered = [];
angular.forEach(items, function(item) {
filtered.push(item);
});
filtered.sort(function (a, b) {
return (strRef(a, field) > strRef(a, field) ? 1 : -1);
});
if(reverse) filtered.reverse();
return filtered;
};
});
Which can then be used like
<div ng-repeat="(key, value) in items | orderObjectBy:'field.any.deep':true">
If you need old browser support, you will need to define the reduce function (this is only available in ECMA-262 mozilla.org)
// Production steps of ECMA-262, Edition 5, 15.4.4.21
// Reference: http://es5.github.io/#x15.4.4.21
if (!Array.prototype.reduce) {
Array.prototype.reduce = function(callback /*, initialValue*/) {
'use strict';
if (this == null) {
throw new TypeError('Array.prototype.reduce called on null or undefined');
}
if (typeof callback !== 'function') {
throw new TypeError(callback + ' is not a function');
}
var t = Object(this), len = t.length >>> 0, k = 0, value;
if (arguments.length == 2) {
value = arguments[1];
} else {
while (k < len && !(k in t)) {
k++;
}
if (k >= len) {
throw new TypeError('Reduce of empty array with no initial value');
}
value = t[k++];
}
for (; k < len; k++) {
if (k in t) {
value = callback(value, t[k], k, t);
}
}
return value;
};
}
That's because you are using JSON Object. When you face such problems then change your JSON Object to JSON Array Object.
For Example,
{"India":"IN","America":"US","United Kingdon":"UK"} json object
[{"country":"India","countryId":"IN"},{"country":"America","countryId":"US"},{"country":"United Kingdon","countryId":"UK"}]
Sorry for bringing this up after a year, but there is an new, easier solution, which works for Angular v1.3.0-rc.5 and later.
It is mentioned in the docs: "If no property is provided, (e.g. '+') then the array element itself is used to compare where sorting". So, the solution will be:
ng-repeat="friend in friends | orderBy:'-'" or
ng-repeat="friend in friends | orderBy:'+':true"
This solution seems to be better because it does not modify an array and does not require additional computational resources (at least in our code). I've read all existing answers and still prefer this one to them.
I had gotten frustrated with this problem myself and so I modified the filter that was created by @Trevor Senior as I was running into an issue with my console saying that it could not use the reverse method. I also, wanted to keep the integrity of the object because this is what Angular is originally using in a ng-repeat directive. In this case I used the input of stupid (key) because the console will get upset saying there are duplicates and in my case I needed to track by $index.
Filter:
angular.module('main').filter('reverse', function() {
return function(stupid, items) {
var itemss = items.files;
itemss = itemss.reverse();
return items.files = itemss;
};
});
HTML:
<div ng-repeat="items in items track by $index | reverse: items">
If you are using angularjs version 1.4.4 and above,an easy way to sort is using the "$index".
<ul>
<li ng-repeat="friend in friends|orderBy:$index:true">{{friend.name}}</li>
</ul>
You can reverse by the $index parameter
<tr ng-repeat="friend in friends | orderBy:'$index':true">
The orderBy filter performs a stable sorting as of Angular 1.4.5. (See the GitHub pull request https://github.com/angular/angular.js/pull/12408.)
So it is sufficient to use a constant predicate and reverse set to true:
<div ng-repeat="friend in friends | orderBy:0:true">{{friend.name}}</div>
You can just call a method on your scope to reverse it for you, like this:
<!doctype html>
<html ng-app="myApp">
<head>
<script src="http://code.jquery.com/jquery-1.9.1.min.js"></script>
<script src="http://code.angularjs.org/1.0.5/angular.min.js"></script>
<script>
angular.module('myApp', []).controller('Ctrl', function($scope) {
$scope.items = [1, 2, 3, 4];
$scope.reverse = function(array) {
var copy = [].concat(array);
return copy.reverse();
}
});
</script>
</head>
<body ng-controller="Ctrl">
<ul>
<li ng-repeat="item in items">{{item}}</li>
</ul>
<ul>
<li ng-repeat="item in reverse(items)">{{item}}</li>
</ul>
</body>
</html>
Note that the $scope.reverse creates a copy of the array since Array.prototype.reverse modifies the original array.
Im adding one answer that no one mentioned. I would try to make the server do it if you have one. Clientside filtering can be dangerous if the server returns a lot of records. Because you might be forced to add paging. If you have paging from the server then the client filter on order, would be in the current page. Which would confuse the end user. So if you have a server, then send the orderby with the call and let the server return it.
Source: Stackoverflow.com