how to stop Javascript forEach?
You can't break from a forEach
. I can think of three ways to fake it, though.
1. The Ugly Way: pass a second argument to forEach
to use as context, and store a boolean in there, then use an if
. This looks awful.
2. The Controversial Way: surround the whole thing in a try-catch
block and throw an exception when you want to break. This looks pretty bad and may affect performance, but can be encapsulated.
3. The Fun Way: use every()
.
['a', 'b', 'c'].every(function(element, index) {
// Do your thing, then:
if (you_want_to_break) return false
else return true
})
You can use some()
instead, if you'd rather return true
to break.
Short circuit Array.forEach like calling break
There's no built-in ability to break
in forEach
. To interrupt execution you would have to throw an exception of some sort. eg.
var BreakException = {};
try { [1, 2, 3].forEach(function(el) { console.log(el); if (el === 2) throw BreakException; });} catch (e) { if (e !== BreakException) throw e;}
How to exit out of javascript forEach loop
According to the MDN web docs:
There is no way to stop or break a forEach() loop other than by
throwing an exception.
Reference: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/forEach
How do I exit an Array.forEach loop early?
Rather than using Array.forEach
, you can use Array.some
(see docs). This function iterates over the elements of the array, checking to see if any element meets a certain condition. If an element is found that meets the condition, the function stops iteration, and returns true
. If not, the function returns false
. This means that you can also skip the step of initializing conditionMet
to false
.
Your code can therefore be simplified as:
let conditionMet = numbers.some(number => (number % 3 === 0));
How to break out from foreach loop in javascript
Use a for
loop instead of .forEach()
var myObj = [{"a": "1","b": null},{"a": "2","b": 5}]
var result = false
for(var call of myObj) {
console.log(call)
var a = call['a'], b = call['b']
if(a == null || b == null) {
result = false
break
}
}
How to break ForEach Loop in TypeScript
It is not possible to break from forEach()
normally.
Alternatively you can use Array.every() because you wish to return false
while breaking the loop.
If you want to return true, then you can use Array.some()
this.tab.committee.ratings.every(element => {
const _fo = this.isEmptyOrNull(element.ratings.finalOutcome.finaloutlook);
const _foreign = this.isEmptyOrNull(element.ratings.finalOutcome.foreign);
const _local = this.isEmptyOrNull(element.ratings.finalOutcome.local);
const _tally = element.ratings.finalOutcome.voteTally.maj + element.ratings.finalOutcome.voteTally.dis;
if (_fo == false && _foreign == false && _local == false) {
if (_tally > 0) {
**return count = false;**
}
} else {
if (_tally < 0) {
**return count = false;**
}
}
});
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