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Cheat Sheets/JavaScript Array Methods

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JavaScript Array Methods

Complete array method reference with examples

JavaScriptArraysMethods

Mutating Methods

push()

arr.push(item)

Add to end

pop()

arr.pop()

Remove from end

shift()

arr.shift()

Remove from start

unshift()

arr.unshift(item)

Add to start

splice()

arr.splice(start, count, ...items)

Insert/remove at index

sort()

arr.sort((a, b) => a - b)

Sort in place

reverse()

arr.reverse()

Reverse in place

Non-Mutating Methods

map()

arr.map(x => x * 2)

Transform each element

filter()

arr.filter(x => x > 5)

Keep elements matching condition

reduce()

arr.reduce((acc, x) => acc + x, 0)

Accumulate to single value

find()

arr.find(x => x.id === 1)

Find first matching element

includes()

arr.includes(item)

Check if item exists

flat()

arr.flat(2)

Flatten nested arrays

flatMap()

arr.flatMap(x => [x, x * 2])

Map + flatten one level