How to swap two array elements in JavaScript
How do you swap 2 elements in an array, in JavaScript?
Suppose we have an array a
which contains 5 letters.
const a = ['a', 'b', 'c', 'e', 'd']
We want to swap element at index 4 (‘d’ in this case) with the element at index 3 (‘e’ in this case).
We can use a temporary item tmp
to store the value of #4, then we put #3 in place of #4, and we assign the temporary item to #3:
const tmp = a[4]
a[4] = a[3]
a[3] = tmp
Another option, which does not involve declaring a temporary variable, is to use this syntax:
const a = ['a', 'b', 'c', 'e', 'd'];
[a[3], a[4]] = [a[4], a[3]]
Now the array a
will be correctly ordered as we want.
a //[ 'a', 'b', 'c', 'd', 'e' ]
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