I have an angular foreach loop and i want to break from loop if i match a value. The following code does not work.
angular.forEach([0,1,2], function(count){
if(count == 1){
break;
}
});
How can i get this?
There's no way to do this. See https://github.com/angular/angular.js/issues/263. Depending on what you're doing you can use a boolean to just not going into the body of the loop. Something like:
var keepGoing = true;
angular.forEach([0,1,2], function(count){
if(keepGoing) {
if(count == 1){
keepGoing = false;
}
}
});
The angular.forEach loop can't break on a condition match.
My personal advice is to use a NATIVE FOR loop instead of angular.forEach.
The NATIVE FOR loop is around 90% faster then other for loops.
USE FOR loop IN ANGULAR:
var numbers = [0, 1, 2, 3, 4, 5];
for (var i = 0, len = numbers.length; i < len; i++) {
if (numbers[i] === 1) {
console.log('Loop is going to break.');
break;
}
console.log('Loop will continue.');
}
please use some or every instances of ForEach,
Array.prototype.some:
some is much the same as forEach but it break when the callback returns true
Array.prototype.every:
every is almost identical to some except it's expecting false to break the loop.
Example for some:
var ary = ["JavaScript", "Java", "CoffeeScript", "TypeScript"];
ary.some(function (value, index, _ary) {
console.log(index + ": " + value);
return value === "JavaScript";
});
Example for every:
var ary = ["JavaScript", "Java", "CoffeeScript", "TypeScript"];
ary.every(function(value, index, _ary) {
console.log(index + ": " + value);
return value.indexOf("Script") > -1;
});
Find more information
http://www.jsnoob.com/2013/11/26/how-to-break-the-foreach/
Use the Array Some Method
var exists = [0,1,2].some(function(count){
return count == 1
});
exists will return true, and you can use this as a variable in your function
if(exists){
console.log('this is true!')
}
As far as I know, Angular doesn't provide such a function. You may want to use underscore's find() function for this (it's basically a forEach which breaks out of the loop once the function returns true).
If you use jQuery (hence not jqLite) in conjunction with AngularJS you can iterate with $.each - which allows breaking and continuing based on boolean return value expression.
JSFiddle:
Javascript:
var array = ['foo', 'bar', 'yay'];
$.each(array, function(index, element){
if (element === 'foo') {
return true; // continue
}
console.log(this);
if (element === 'bar') {
return false; // break
}
});
Note:
Though using jQuery is not bad, both native Array.some or Array.every functions are recommended by MDN as you can read at native forEach documentation:
"There is no way to stop or break a forEach loop. The solution is to use Array.every or Array.some"
Following examples are provided by MDN:
Array.some:
function isBigEnough(element, index, array){
return (element >= 10);
}
var passed = [2, 5, 8, 1, 4].some(isBigEnough);
// passed is false
passed = [12, 5, 8, 1, 4].some(isBigEnough);
// passed is true
Array.every:
function isBigEnough(element, index, array){
return (element >= 10);
}
var passed = [12, 5, 8, 130, 44].every(isBigEnough);
// passed is false
passed = [12, 54, 18, 130, 44].every(isBigEnough);
// passed is true
Concretely, you can exit of a forEach loop, and of any place, throw an exception.
try {
angular.forEach([1,2,3], function(num) {
if (num === 2) throw Error();
});
} catch(e) {
// anything
}
However, it is better if you use other library or implement your own function, a find function in this case, so your code is most high-level.
As the other answers state, Angular doesn't provide this functionality. jQuery does however, and if you have loaded jQuery as well as Angular, you can use
jQuery.each ( array, function ( index, value) {
if(condition) return false; // this will cause a break in the iteration
})
Normally there is no way to break an "each" loop in javascript. What can be done usually is to use "short circuit" method.
array.forEach(function(item) {
// if the condition is not met, move on to the next round of iteration.
if (!condition) return;
// if the condition is met, do your logic here
console.log('do stuff.')
}break isn't possible to achieve in angular forEach, we need to modify forEach to do that.
$scope.myuser = [{name: "Ravi"}, {name: "Bhushan"}, {name: "Thakur"}];
angular.forEach($scope.myuser, function(name){
if(name == "Bhushan") {
alert(name);
return forEach.break();
//break() is a function that returns an immutable object,e.g. an empty string
}
});
You can use this:
var count = 0;
var arr = [0,1,2];
for(var i in arr){
if(count == 1) break;
//console.log(arr[i]);
}
Try this as break;
angular.forEach([0,1,2], function(count){
if(count == 1){
return true;
}
});
var ary = ["JavaScript", "Java", "CoffeeScript", "TypeScript"];
var keepGoing = true;
ary.forEach(function(value, index, _ary) {
console.log(index)
keepGoing = true;
ary.forEach(function(value, index, _ary) {
if(keepGoing){
if(index==2){
keepGoing=false;
}
else{
console.log(value)
}
}
});
});
$scope.arr = [0, 1, 2];
$scope.dict = {}
for ( var i=0; i < $scope.arr.length; i++ ) {
if ( $scope.arr[i] == 1 ) {
$scope.exists = 'yes, 1 exists';
break;
}
}
if ( $scope.exists ) {
angular.forEach ( $scope.arr, function ( value, index ) {
$scope.dict[index] = value;
});
}
I would prefer to do this by return. Put the looping part in private function and return when you want to break the loop.
I realise this is old, but an array filter may do what you need:
var arr = [0, 1, 2].filter(function (count) {
return count < 1;
});
You can then run arr.forEach and other array functions.
I realise that if you intend to cut down on loop operations altogether, this will probably not do what you want. For that you best use while.
This example works. Try it.
var array = [0,1,2];
for( var i = 0, ii = array.length; i < ii; i++){
if(i === 1){
break;
}
}
Use Return to break the loop.
angular.forEach([0,1,2], function(count){
if(count == 1) {
return;
}
});
I would use return instead of break.
angular.forEach([0,1,2], function(count){
if(count == 1){
return;
}
});
Works like a charm.
Just add $index and do the following:
angular.forEach([0,1,2], function(count, $index) {
if($index !== 1) {
// do stuff
}
}
来源：https://stackoverflow.com/questions/13843972/angular-js-break-foreach