includes()
The includes() method determines whether a string contains the given characters within it or not. This method returns true if the string contains the characters, otherwise, it returns false.
const str = "JavaScript is fun";
// check if message includes the string "fun"
let result = str.includes("fun");
console.log(result);
// Output: true
Slice()
The slice() method returns a shallow copy of a portion of an array into a new array object selected from start to end where start and end represent the index of items in that array.
const message = "JavaScript";
// slice the substring from index 0 to 4
let result = message.slice(0, 4);
console.log(result);
// Output: Java
concat()
The concat() method is used to merge two or more arrays. This method does not change the existing arrays but instead returns a new array.
let name = "";
// joint arguments string
let joinedString = name.concat("Riyaz", " Ahemad");
console.log(joinedString);
// Output: Riyaz Ahemad
Replace()
The replace() method replaces a specific value with another value in a string. Replace method replaces only the first match.
const message = "Foot ball";
// replace the first Foot with Bat
let result = message.replace('Foot', 'Bat');
console.log(result);
// Output: Bat ball
toLowerCase()
The toLowerCase() is a string method that converts a string to lowercase letters. The toLowerCase() method does not change the original string.
const name = "DOG";
// convert name into lowercase
const lowerName = name.toLowerCase();
console.log(lowerName);
// Output: dog
toUpperCase()
The toUpperCase() is a string method that converts a string to uppercase letters. The toUpperCase() method does not change the original string.
const name = "dog";
// convert message to uppercase
const upperName = name.toUpperCase();
console.log(upperName);
// Output: DOG
indexOf()
The indexOf() is a string method that returns the position of the first occurrence of a specified value in a string. This method returns -1 if the value is not found.
const name = "Hello world";
// returns index of 'w'
const index = name.indexOf("w");
console.log('index: ' + index); // index: 6
lastIndexOf()
The lastIndexOf() function will search and return the index of the last occurrence of a mentioned character within the string. If a mentioned character is not found, it will return -1.
// defining a string
var str = "Programming";
var substr = "g";
// find last occurrence of "g" in str
var result = str.lastIndexOf(substr);
console.log(result); // Output: 10
search()
It will search() and test for a match in a string and returns the index of the match. If a mentioned character is not found, it will return -1.
let message= "I love JavaScript.";
// pattern that searches the first occurence of an uppercase character
let regExp = /[J]/;
// searching for a match between regExp and given string
let indexReg = message.search(regExp);
console.log(indexReg); // Output: 0
substring()
substring() is the same as the slice() method. The only difference is that substring() does not accept negative indexes.
const message = "Namste Javascript";
// get the substring starting from index 0 to 6
let result = message.substring(0, 6);
console.log(result);
// Output: Namste
trim()
The trim() Method removes whitespace from both ends of a string.
const greeting = " Hello world ";
// remove whitespaces from both side
const NewGreeting = greeting.trim();
console.log(NewGreeting);
// Output: Hello world
trimEnd()
The trimEnd() Method removes whitespace from the end of a string.
trimStart()
The trimStart() Method removes whitespace from the Start of a string.
repeat()
The repeat() method returns a new string with a specified number of copies of the string it was called on.
let str = "NAMASTE ";
//repeating the given string 2 times
let result = str.repeat(2);
console.log(result)
//OUTPUT: NAMASTE NAMASTE