Array push and pop

Push and unshift

We can use .push() to add a new item to the end of the array, whereas .unshift() adds an item to the beginning.

js

const authors = [
  'Chinua Achebe',
  'Toni Morrison',
  'Gabriel García Márquez',
  'Arundhati Roy',
  'Marjane Satrapi'
]

authors.push('Amy Tan') // add the the end
authors.unshift('Sandra Cisneros') // add to the beginning

console.log(authors)

output

[
  'Sandra Cisneros',
  'Chinua Achebe',
  'Toni Morrison',
  'Gabriel García Márquez',
  'Arundhati Roy',
  'Marjane Satrapi',
  'Amy Tan'
]

TIP

Note that .push and .unshift modify the array "in place", meaning they do not return a new array but modify an existing one. If you need to modify an array and return it, you need to use the methods and then return on a different line. For example,

function shiftRight(arr) {
  const last = arr.pop()
  arr.unshift(last)
  return arr
}

Pop and shift

The .pop() method will remove and return the final item of the array, whereas .shift() removes and returns the first item.

js

const authors = [
  'Chinua Achebe',
  'Toni Morrison',
  'Gabriel García Márquez',
  'Arundhati Roy',
  'Marjane Satrapi'
]

const lastAuthor = authors.pop()
const firstAuthor = authors.shift()

console.log(lastAuthor)
console.log(firstAuthor)
console.log(authors)

output

Marjane Satrapi
Chinua Achebe
[
  'Toni Morrison',
  'Gabriel García Márquez',
  'Arundhati Roy'
]

TIP

If all you want to do is remove an item from an array, you can just do

authors.pop()
authors.shift()

You don't need to assign the removed item to a variable if it's not needed.