Array Methods

1.Array Length
The length property returns the length (size) of an array
The length property can also be used to set the length of an array

let a = ["HTML", "CSS", "JS", "React"];
// console.log(a.length);
a.length=2;
console.log(a);

Output:4
(2) ['HTML', 'CSS']

2.toString()
Converts the given value into the string with each element separated by commas

let b  = ["HTML", "CSS", "JS", "React"];
// let c = b.toString();
// console.log(c);
console.log(b.toString());

Output:HTML,CSS,JS,React

3.at()
ES2022 introduced the array method at()
Returns an indexed element from an array

let d  = ["HTML", "CSS", "JS", "React"]; 
//    let e = d.at(2);
//    console.log(e);
console.log(d.at(3));

Output:React

4.join()
The join() method also joins all array elements into a string.
It behaves just like toString(), but in addition you can specify the separator

let f = ["HTML", "CSS", "JS", "React"];
console.log(f.join('|'));

Output:HTML|CSS|JS|React

5.pop()
Used to remove elements from the end of an array

 let g = ["HTML", "CSS", "JS", "React"];
 g.pop();
 console.log(g);

Output: ['HTML', 'CSS', 'JS']

6.push()
adds a new element to an array (at the end)

let h = ["HTML", "CSS", "JS", "React"];
h.push("java");
console.log(h);

Output: ['HTML', 'CSS', 'JS', 'React', 'java']

7.shift()
Removes the first array element and "shifts" all other elements to a lower index

let i = ["HTML", "CSS", "JS", "React"];
i.shift();
console.log(i);

Output: ['CSS', 'JS', 'React']

8.unshift()
adds a new element to an array (at the beginning), and "unshifts" older elements

let j = ["HTML", "CSS", "JS", "React"];
j.unshift("java");
console.log(j);

Output: ['java', 'HTML', 'CSS', 'JS', 'React']

9.isArray()
ECMAScript 5 (JavaScript 2009) added the new method Array.isArray() to JavaScript
isArray() is a built-in method of the Array object. It checks whether a value is an array

let k = ["HTML", "CSS", "JS", "React"];
console.log(Array.isArray(k));

Output:true

10.delete()
Used to delete the element in the array

let l = ["HTML", "CSS", "JS", "React"];
delete l[0];
console.log(l);
// console.log(l[0]);

Output:[empty, 'CSS', 'JS', 'React']

11.concat()
Used to concatenate two or more arrays and it gives the merged array
This does not change the existing arrays. It always returns a new array

let m = ["HTML", "CSS", "JS", "React"];
let n=["java","python"];
let o=m.concat(n);
console.log(o);

Output:['HTML', 'CSS', 'JS', 'React', 'java', 'python']

12.copyWithin
copies array elements to another position in an array

let p = ["HTML", "CSS", "JS", "React"];
p.copyWithin(2,0);
console.log(p);

Output: ['HTML', 'CSS', 'HTML', 'CSS']

13.flat()
Used to flatten the array i.e. it merges all the given array and reduces all the nesting present in it

let q = ["HTML", "CSS", "JS",[1,2], "React",['5','6']];
let r=q.flat();
console.log(r);

Output:['HTML', 'CSS', 'JS', 1, 2, 'React', '5', '6']

14.splice()
used to Insert and Remove elements in between the Array

let s = ["HTML", "CSS", "JS", "React"];
// s.splice(2 ,2);
// s.splice(1,0,"python");
s.splice(2,0,"java")
console.log(s);

Output:['HTML', 'CSS', 'java', 'JS', 'React']

15.slice()
Returns a new array containing a portion of the original array, based on the start and end index provided as arguments
Does not change the original array

let t = ["HTML", "CSS", "JS", "React","java","python"];
// let u=t.slice();
let u=t.slice(1,4);
console.log(u);
// console.log(t);

Output:['CSS', 'JS', 'React']