JavaScript array methods
Updated 2026-02-15
map, filter, reduce, find, some, every, flatMap, and more. Immutable patterns and chaining.
Iteration and transform
map(fn), filter(fn), reduce(fn, init), forEach(fn). find(fn), findIndex(fn). some(fn), every(fn). flat(), flatMap(fn).
Add/remove and order
push, pop, shift, unshift. splice(i, n, ...items). slice(start, end). concat(arr). sort(compareFn). reverse().
Immutable patterns
[...arr], arr.filter(), arr.map(), arr.slice(). [...arr, item], arr.slice(0, i).concat(arr.slice(i+1)).