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JavaScript

Joseph Bertino
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Joseph Bertino
Full Stack JavaScript Techdegree Student 14,652 Points
Posted by Joseph Bertino
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Joseph Bertino
Full Stack JavaScript Techdegree Student 14,652 Points

Alternative to for() loops?

I know this is JavaScript (lol), but personally I think using the for() loop to iterate through a list as we have been doing is both clunky and ugly, and I prefer a more "Pythonic" way of iterating through a list.

So I've been using the following one-liner:

Array.prototype.forEach.call(list, listElem => { <do something with listElem>; });

Is there a better alternative to this approach that avoids the for loop entirely and is still succinct?

2 Answers

Robert Manolis
STAFF
Robert Manolis
Treehouse Guest Teacher
Robert Manolis
Robert Manolis
Treehouse Guest Teacher

Hi Joseph Bertino, give this a try. :thumbsup:

[...list].forEach((listItem, index, list) => { console.log(listItem, index, list); });
Joseph Bertino
seal-mask
.a{fill-rule:evenodd;}techdegree
Joseph Bertino
Full Stack JavaScript Techdegree Student 14,652 Points
Joseph Bertino
.a{fill-rule:evenodd;}techdegree
Joseph Bertino
Full Stack JavaScript Techdegree Student 14,652 Points

Note: When playing around in a workspace, I even got this to work without the spread operator

list.forEach((listItem, index, list) => { console.log(listItem, index, list); });
Robert Manolis
Robert Manolis
Treehouse Guest Teacher
Robert Manolis
Robert Manolis
Treehouse Guest Teacher

Hey Joseph Bertino, yeah, if you're working with a collection that allows for the use of array methods, then you won't need the spread operator.

For example, if you use the getElementsByTagName or getElementsByClassName methods, they return an HTMLcollection, which won't work with those higher order functions like .forEach(). So to use forEach on an HTMLcollection, you need to first turn the collection into an array.

But if you use the querySelectorAll method, you get back a NodeList instead, and you can use .forEach() directly on a NodeList without the spread operator.