JS: Array.prototype.shift

By Xah Lee. Date: . Last updated: .
xArray.shift()
  • Remove and return the first item.
  • If xArray is empty, return undefined.
// example of shift
const xx = ["a", "b", "c"];
const yy = xx.shift();

console.log(yy);
// a

// original changed
console.log(xx);
// [ "b", "c" ]
// shift on empty array return undefined
const xx = [];
const yy = xx.shift();
console.assert(yy === undefined);