Is it an antipattern to set an array length in JavaScript?

Question

Is it bad to use code like:

var a = [1,2,3,4];
a.length = 2; // 3 and 4 are removed

Does it have decent browser support? Do the removed val

Answer 1

It's better to use slice because your intentions are clear.

var truncated = a.slice(0,2)

Slice does create a new array though.

If that is an issue for you then there is nothing wrong with modifying the length property.

It's actually the fastest way of truncation and supported in all browsers. jsperf