How to insert a new element in between all elements of a JS array?

Question

I have an array [a, b, c]. I want to be able to insert a value between each elements of this array like that: [0, a, 0, b, 0, c, 0].

I gues

Answer 1

If you want to insert elements only after existing ones:

console.log(["a", "b", "c"].map(i => [i, 0]).flat())