Array Methods

Array methods are helpers that change lists or build new lists.

Some edit the same array. Some return a fresh one.

Think of sorting toys, filtering toys, or lining them up.

push and pop

push adds at the end. pop removes from the end.

unshift and shift

unshift adds at the start. shift removes from the start.

includes and indexOf

includes asks if an item is there.

indexOf tells the seat number, or -1 if missing.

map

map builds a new array by changing each item.

filter and find

filter keeps items that pass a test.

find returns the first item that passes.

join

join glues array items into one string.

Tip: Ask yourself if a method changes the old array or returns a new one. That question prevents many bugs.