Name
Array.shift( ) — shift array elements down
Availability
JavaScript 1.2; JScript 5.5; ECMAScript v3
Synopsis
array
.shift( )
Returns
The former first element of the array.
Description
shift( )
removes
and returns the first element of array
,
shifting all subsequent elements down one place to occupy the newly
vacant space at the start of the array. If the array is empty,
shift( )
does nothing and returns the
undefined
value. Note that shift( )
does not create a new array; instead, it modifies
array
directly.
shift( )
is similar to Array.pop( )
, except it operates on the beginning of an array rather
than the end. shift( )
is often used in
conjunction with unshift( )
.
Example
var a = [1, [2,3], 4] a.shift( ); // Returns 1; a = [[2,3], 4] a.shift( ); // Returns [2,3]; a = [4]
See Also
Get JavaScript: The Definitive Guide, Fourth Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.