unshift - nodef/extra-iterable GitHub Wiki

Add values to the start.

Similar: push, pop, shift, unshift.

function unshift(x, ...vs)
// x:  an iterable
// vs: values to add

const xiterable = require('extra-iterable');

var x = [3, 4];
[...xiterable.unshift(x, 2)];
// → [2, 3, 4]

[...xiterable.unshift(x, 1, 2)];
// → [1, 2, 3, 4]

References

• Array.prototype.unshift: MDN web docs
• array_unshift: PHP
• Array.unshift: Ruby
• immutable-prototype: @azu