insert array into array js code example

Example 1: js array add element

array.push(element)

Example 2: javascript add array to array at index

a1.splice(2, 0, ...a2);

Example 3: add item to array javascript

const arr1 = [1,2,3]
const newValue = 4
const newData = [...arr1, obj] // [1,2,3,4]