Name
Array.unshift() — insert elements at the beginning of an array
Synopsis
array
.
unshift
(
value
,
...)
Arguments
value, ...
One or more values that are inserted at the start of
array
.
Returns
The new length of the array.
Description
unshift()
inserts its
arguments at the beginning of array
,
shifting the existing elements to higher indexes to make room. The
first argument to shift()
becomes
the new element 0 of the array; the second argument, if any, becomes
the new element 1; and so on. Note that unshift()
does not create a new array; it
modifies array
directly.
Example
unshift()
is often used in
conjunction with shift()
. For
example:
var
a
=
[];
// a:[]
a
.
unshift
(
1
);
// a:[1] Returns: 1
a
.
unshift
(
22
);
// a:[22,1] Returns: 2
a
.
shift
();
// a:[1] Returns: 22
a
.
unshift
(
33
,[
4
,
5
]);
// a:[33,[4,5],1] Returns: 3
See Also
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