Arrays + functions: forEach()

The forEach() of an array instance is used to execute a function, which we call “callback function”, for all elements of an array. This callback function is passed the current item:

const list = [1, 2, 3]

list.forEach(element => {
  console.log(element * 2)
})

It’s similar to map(), however nothing is returned from forEach while using map you get a new array with the result of the function executed in the callback.

You can also get the index of the element as the second parameter to the callback function:

const list = [1, 2, 3]

list.forEach((element, index) => {
  console.log(element, index)
})

Lessons this unit:

0: Introduction
1: map()
2: filter()
3: reduce()
4: sort()
5: find() and findIndex()
6: ▶︎ forEach()