Fastest way to duplicate an array in JavaScript - slice vs. 'for' loop

Question

In order to duplicate an array in JavaScript: which of the following is faster to use?

###Slice method

var dup_array = original_array.slice();
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Answer 1

ECMAScript 2015 way with the Spread operator:

Basic examples:

var copyOfOldArray = [...oldArray]
var twoArraysBecomeOne = [...firstArray, ..seccondArray]

Try in the browser console:

var oldArray = [1, 2, 3]
var copyOfOldArray = [...oldArray]
console.log(oldArray)
console.log(copyOfOldArray)

var firstArray = [5, 6, 7]
var seccondArray = ["a", "b", "c"]
var twoArraysBecomOne = [...firstArray, ...seccondArray]
console.log(twoArraysBecomOne);

References

• 6 Great Uses of the Spread Operator
• Spread syntax