What is String?
A string in programming is a sequence of characters (letters, numbers, symbols, and spaces) typically used to represent text. Strings are often enclosed in quotation marks (" " or ' ').
String have some in build methods which can used in manipulation of string.
String Methods:-
Length Property
It is used to check the length of the string.
let fname = 'Priya'
console.log(fname.length); //5
CharAt()
The charAt() method in JavaScript returns the character at a specified index in a string.
let str = "Hello, World!";
console.log(str.charAt(0)); // H
concat()
The concat() method in JavaScript is used to join two or more strings together. It does not change the original strings but returns a new concatenated string.
let str1 = "Hello";
let str2 = "World";
let str3 = "!";
console.log(str1.concat(", ", str2, str3)); // "Hello, World!"
Inculdes()
Checks if the string contains a substring (returns true or false).
//string.includes('str-elem', start-index)
let sentence = "The quick brown fox jumps over the lazy dog.";
onsole.log(sentence.includes("quick")); // true
console.log(sentence.includes("Quick")); // false
console.log(sentence.includes("lazy", 30)); // true
IndexOf()
Returns the index of the first occurrence of a substring.
let sentence = "The quick brown fox jumps over the lazy dog.";
console.log(sentence.indexOf("quick")); // 4
Slice(startIndex, endIndex)
Similar to substring() but supports negative indices to count from the end.
let sentence = "The quick brown fox jumps over the lazy dog.";
console.log(sentence.slice(4, 9)); // "quick"
Split(separator, liimit)
Splits the string into an array at the specified separator.
let sentence = "The quick brown fox jumps over the lazy dog.";
console.log(sentence.split(" "));
ToLowerCase()
Converts the string to lowercase.
let sentence = "The Quick Brown Fox.";
console.log(sentence.toLowerCase()); // "the quick brown fox."
ToUpperCase()
Converts the string to uppercase.
let sentence = "The Quick Brown Fox.";
console.log(sentence.toUpperCase()); // "THE QUICK BROWN FOX."
Trim()
Removes leading and trailing whitespace.
let greeting = " Hello, World! ";
console.log(greeting.trim()); // "Hello, World!"
Replace(searchValue, newValue)
Replaces occurrences of a substring with another substring.
let sentence = "The quick brown fox jumps over the lazy dog.";
console.log(sentence.replace("fox", "cat"));
//The quick brown cat jumps over the lazy dog.
padStart() and padEnd()
It will give padding at start or at the end.
const originalString = "hello";
const paddedString = originalString.padStart(10, "Hey! "); // // "-----hello"
const paddedString2 = originalString.padEnd(12, " Shweta"); // "hello-----"
Repeat()
Repeats the string count times.
const originalString = "hello";
const repeatedString = originalString.repeat(3); // "hellohellohello"
console.log(repeatedString);
StartsWith()
Checks if the string starts with the specified prefix (returns true or false).
const originalString = "hello world";
const startsWithHello = originalString.startsWith("hello"); // true
EndsWith()
Checks if the string ends with the specified suffix (returns true or false).
const originalString = "hello world";
const endsWithWorld = originalString.endsWith("world"); // true
CharCodeAt()
Returns the Unicode value of the character at the specified index.
let str = "Hello";
console.log(str.charCodeAt(1)); // 101 (Unicode for 'e')