Length

Arrays have a property called length, and it's pretty much exactly as it sounds, it's the length of the array.

var array = [1 , 2, 3];

// Result: l = 3
var l = array.length;

var array = [1, 1, 2, 3, 5, 8];
var l = array.length;
var a = 6;

assert (a === 6)