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

In ES6, you can simply utilize the Spread syntax.

Example:

let arr = ['a', 'b', 'c'];
let arr2 = [...arr];

Please note that the spread operator generates a completely new array, so modifying one won't affect the other.

Example:

arr2.push('d') // becomes ['a', 'b', 'c', 'd']
console.log(arr) // while arr retains its values ['a', 'b', 'c']