A cheatsheet for choosing JavaScript array methods

array_methods_cheats.md

Choosing an array method

I want to...

Mutate the original array

• Add to original:

arr.push
arr.unshift

• Remove from original:

arr.pop
arr.shift
arr.splice

Return a new array

• Computed from original

arr.map

• Filtered using condition

arr.filter

• Portion of original

arr.filter

• Adding original to other

arr.concat

• Flattening the original

arr.flat
arr.flatMap

Get an array index

• Based on value

arr.indexOf

• Based on test condition

arr.findIndex

Get an array element

• Based on a text condition

arr.find

Know if the array includes...

• Based on value

arr.includes

• Based on test condition

arr.some
arr.every

Form array from a string

• Based on separsator string

arr.join

Transform the array to a new value

• Based on accumulator note: boils down array to single value of any type

arr.reduce

Loop over the array without returning a value

• Based on callback note: does not create new array, just loops over it

arr.forEach

nice :)