The primitive variable just stores one value. A lot of time it’s very difficult to manage multiple variables so to avoid this problem we need storage to store multiple elements inside one variable. So basically javascript array is an ordered series or arrangement. For more details, you can see MDN. But it’s very useful to maintain multiple values at once.
Array is an ordered series or arrangement.
Creation or Declaration
var arr = []; //empty array
var arr = [1, 2, 3, 4, 5] //array with integer elements
var fruits = ["Apple", "Mango", "Orange"]; //array with string elements
Get length
console.log(arr.length); //5
Get value
console.log(arr[2]); //3
Reset value
arr.length = 0;
or
arr.length = [];
Accessing all value
for (var i = 0, len = fruits.length; i < len; i++) {
console.log(fruits[i]);
}
// Apple, Mango, Orange
Find type
// First solution
Array.isArray(fruits); // returns true
//Second solution
fruits instanceof Array // returns true
//Third solution
function isArr(coll) {
return coll.constructor.toString().indexOf("Array") > -1;
}
isArr(fruits); // returns true
Add and remove element
We have three ways to add and remove an element from an array. We have different use cases.
var arr = [];
//Frist way
arr[0] = "zeroth";
console.log(arr); // zeroth
//Second way - work as stack format value add after last index of array
arr.push("first");
console.log(arr); // zeroth, <b>first</b>
//Third way - work as queue format value add before zeroth index
arr.unshift("second");
console.log(arr); // <b>second</b>, zeroth, first
Also see: Variables and data types in javascript
