May 28, 2023

How can I add new array elements at the beginning of an array in JavaScript?

Use unshift. It’s like push, except it adds elements to the beginning of the array instead of the end.

  • unshift/push – add an element to the beginning/end of an array
  • shift/pop – remove and return the first/last element of an array

A simple diagram…

   unshift -> [array] <- push
   shift   <- [array] -> pop

and chart:

          add  remove  start  end
   push    X                   X
    pop           X            X
unshift    X             X
  shift           X      X

Check out the MDN Array documentation. Virtually every language that has the ability to push/pop elements from an array will also have the ability to unshift/shift (sometimes called push_front/pop_front) elements, you should never have to implement these yourself.

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