Alternative to the 'let' keyword in a loop?

Question

I was having an issue where I was setting up a bunch of timeout calls and I wanted the timeout function to reference the element in the current loop.

This is what the result looked like:

    var createTimedMessages = function(arr, collection){
        var timeLimit = 2000;
        for(var i = 0; i<arr.length; i++){
            let el = arr[i];
            collection.push(el);
            $timeout(function removeElement(){
                collection.removeMatch(el);
            }, timeLimit);
        }
    }

but I realized that this wouldn't work with some slightly older browsers because of lack of support for the let keyword. What is a good workaround?

Note: This is in angular, hence the $timeout rather than setTimeout.

Use a nested function/closure - it's been done (and worked like this) for years. — user2864740, Jun 21 '15 at 01:32
Yep, sorry, just realized that @user2864740 found the better dup target. — tckmn, Jun 21 '15 at 01:33
@Doorknob *But* that question has a better coverage of an IIFE. Putting the two together -> win. — user2864740, Jun 21 '15 at 01:34

score 4 · Answer 1 · answered Jun 21 '15 at 01:33

Use a IIFE:

var createTimedMessages = function(arr, collection) {
    var timeLimit = 2000;
    for (var i = 0; i < arr.length; i++) {
        (function(el) {
            collection.push(el);
            $timeout(function removeElement() {
                collection.removeMatch(el);
            }, timeLimit);
        })(arr[i]);
    }
}

score 0 · Answer 2 · answered Jun 21 '15 at 01:35

0

Self-executing functions should solve the problem:

(function(el, timeLimit) {
    $timeout(/* your code */);
})(arr[i], timeLimit);

answered Jun 21 '15 at 01:35

Rico Herwig

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Alternative to the 'let' keyword in a loop?

2 Answers2

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