JavaScript Glossary: Array unshift() Method
Publikováno: 17.2.2019
Basics
The unshift array method appends a number of values to the start of a given array. It then returns the new length of the array. This method can take a number of argumen...
Basics
The unshift array method appends a number of values to the start of a given array. It then returns the new length of the array. This method can take a number of arguments, each to be added to the array in the specified order.
[1, 2, 3, 4, 5].unshift(0, 0.5)
// [0, 0.5, 1, 2, 3, 4, 5]https://scotch.io/embed/gist/948919ac330599b8d763d906d6b153b4
Unshift mutates the original array and returns the length of the original array after the mutation.
Syntax
const newArray = oldArray.unshift(item1, item2, ...itemN)1 Parameter
item[s] This is the element or multiple elements or items to be added.
Returns a number
The method will return the length of the array after adding the new elements.
Common Uses and Snippets
Add new items to an array
Adding new values to the start of an array maintaining a set order.
https://scotch.io/embed/gist/cd1ae883d3c1c87b0ee780341e33d7ce
Add items to cart
The unshift() method can be used to add new items to the front of an array of objects.
https://scotch.io/embed/gist/cbcf983b0225a854d34331b523b894f1