Adds values to the end.
Alternatives: push, push$.
Similar: push, pop, shift, unshift.
This is part of package extra-array.
array.push(x, ...vs);
// x: an array
// vs: values to add
const array = require("extra-array");
var x = [1, 2];
array.push(x, 3);
// [ 1, 2, 3 ]
array.push(x, 3, 4);
// [ 1, 2, 3, 4 ]