JSFiddle - React, Tailwind, and code Playground

by jfriend00

JavaScript

a1 = [1,2,3,4,5];
a2 = [21,22];

a2.unshift(2, 0);     // put first two params to splice onto front of array
Array.prototype.splice.apply(a1, a2);   // pass array as arguments parameter to splice
alert(a1.join(', '));