var colors = ["white","blue"];
colors.unshift("red"); //add red to beginning of colors
// colors = ["red","white","blue"]
let arr = [4, 5, 6]
arr.unshift(1, 2, 3)
console.log(arr);
// [1, 2, 3, 4, 5, 6]
In JavaScript, you use the unshift() method
to add one or more elements to the beginning
of an array and it returns the array's
length after the new elements have been added.
example:
var colors = ['white', 'blue'];
colors.unshift('red');
console.log(colors);
// colors = ['red', 'white', 'blue']
var numbers = [2, 3, 4, 5];
numbers.unshift(1);
console.log(numbers);
// numbers: [ 1, 2, 3, 4, 5 ]
var arr = [23, 45, 12, 67];
arr = [34, ...arr]; // RESULT : [34,23, 45, 12, 67]
console.log(arr)