DEV Community

loading...

Discussion on: How To For Loop Through Anything in JS

Collapse
fleshmecha profile image

I really hoped this was going to tell me how to write the fastest for loop! Which one is quickest?

Collapse
patarapolw profile image
Pacharapol Withayasakpunt • Edited

jsperf.com/loop-vs-map-vs-foreach/22

So, map and classical for loop. But it is usually more semantically to use forEach rather than map, albeit slow.

for loop isn't so bad, but it depends on the use case.

Collapse
leob profile image
leob

Why is it more semantical to write "arr.forEach(...)" instead of "for (... of arr)" ? Seems merely a matter of syntax and taste to me ...

Thread Thread
jacobmparis profile image
Jacob Paris Author

I would absolutely consider this to be a matter of taste

Thread Thread
patarapolw profile image
Pacharapol Withayasakpunt

I meant arr.forEach() vs arr.map().

for of and for in are another species, and is whether you want it to be functional or procedural. Neither is better than the others.

Collapse
jacobmparis profile image
Jacob Paris Author

That depends what you're measuring

Most of the time a for loop takes up is spent doing logic on each iteration. The amount of time it takes to switch from the end of one iteration to another (which is the only way these differ) is microscopic in comparison.

Unless you're doing many thousands of iterations, performance is the wrong heuristic to help you decide