js add item to beginning of array code example

Example 1: javascript add new array element to start of array

var colors = ["white","blue"];
colors.unshift("red"); //add red to beginning of colors
// colors = ["red","white","blue"]

Example 2: js add element to front of array

//Add element to front of array
var numbers = ["2", "3", "4", "5"];
numbers.unshift("1");
//Result - numbers: ["1", "2", "3", "4", "5"]

Example 3: unshift method in javascript

var name = [ "john" ];
name.unshift( "charlie" );
name.unshift( "joseph", "Jane" );
console.log(name);

//Output will be
[" joseph "," Jane ", " charlie ", " john "]

Example 4: insert element at beginning of array javascript

// Use unshift method if you don't mind mutating issue
// If you want to avoid mutating issue
const array = [3, 2, 1]

const newFirstElement = 4

const newArray = [newFirstElement].concat(array) // [ 4, 3, 2, 1 ]

console.log(newArray);

Example 5: prepend to array javascript

// Build an array of test data.
var data = [ "X" ];

// Unshift data onto the array. Unshift() prepends elements to
// the beginning of the given array. Note that it can take more
// than one argument. In the output, notice that when unshift()
// takes multiple arguments, they are prepended in a right-to-left
// order (mimicing their appearence in the arguments list).
data.unshift( "A" );
data.unshift( "B", "C" );

// Output resultant array.
console.log( data );