How to use JavaScript Array keys()


let a = ["JavaScript","Python","Php","Css","Html"];
let b = a.keys();

for(let key of b){
    console.log(key);
}

Declare three variable a, b and key
Initialize three variable with value of array a = ["JavaScript","Python","Php","Css","Html"], b = a.keys() and key
Array keys() method returns the index number of the given array.
The value of key variable is displayed with the help of console.log inbuilt function

How to use JavaScript Array lastIndexOf()


let a = ["Html", "Css", "JavaScript","Html","Css"];
let b = a.lastIndexOf("Html");
console.log(b);

Declare two variable a and b
Initialize two variable with value of array a = ["Html", "Css", "JavaScript","Html","Css"] and b = a.lastIndexOf("Html")
Array lastIndexOf() method returns the last index of the given element
The value of b variable is displayed with the help of console.log inbuilt function


let c = ["Html", "Css", "JavaScript","Html","Css","JavaScript"];
let d = c.lastIndexOf("Css");
console.log(d);

Declare two variable c and d
Initialize two variable with value of array c = ["Html", "Css", "JavaScript","Html","Css","JavaScript"] and d = c.lastIndexOf("Css")
Array lastIndexOf() method returns the last index of the given element
The value of d variable is displayed with the help of console.log inbuilt function


let a = ["JavaScript","Python","Php","Css","Html"];
let b = a.fill("Java");
console.log(b);


[ 'Java', 'Java', 'Java', 'Java', 'Java' ]

Declare two variable a and b
Initialize two variable with value of array a = ["JavaScript","Python","Php","Css","Html"] and b = a.fill("Java")
Array fill() method fills the elements of the array with the given value.
The value of b variable is displayed with the help of console.log inbuilt function


let c = ["JavaScript","Python","Php","Css","Html"];
let d = c.fill("Java",1,3);
console.log(d);


[ 'JavaScript', 'Java', 'Java', 'Css', 'Html' ]

Declare two variable c and d
Initialize two variable with value of array c = ["JavaScript","Python","Php","Css","Html"] and d = c.fill("Java",1,3)
Array fill() method fills the elements of the array with the given value.
The value of d variable is displayed with the help of console.log inbuilt function


let a = ["JavaScript","Python","Php"];
let b = a.indexOf("Python");
console.log(b);

Declare two variable a and b
Initialize two variable with value of array a = ["JavaScript","Python","Php"] and b = a.includes("Python")
Array IndexOf() method returns the index value of the array if it is found in the given array and returns -1 if it is not found.
The value of b variable is displayed with the help of console.log inbuilt function