JavaScript Array Methods

Quick reference for JavaScript arrays

Iteration

arr.forEach(fn)Iterate over each item

arr.map(fn)New array with fn applied

arr.filter(fn)Items where fn returns true

arr.find(fn)First match

arr.indexOf(val)First index or -1

arr.includes(val)Contains value?

arr.sort(fn)Sort in place

arr.reverse()Reverse array in place

arr.reduce(fn, init)Reduce to single value

arr.concat(arr2)Merge arrays

arr.join(sep)Join array to string

[...arr]Copy array