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JS String

Strings created with single or double quotes works the same.

There is no difference between the two.

1. Creating Strings:

  • You can create strings using string literals or the String() constructor:
					const str1 = 'Hello, world!';
const str2 = "JavaScript is awesome!";
const str3 = new String
('This is a string object.');


2. Accessing Characters:

  • You can access individual characters of a string using square brackets [] and the character’s index, which starts from 0
					console.log(str1[0]); // Outputs: 'H'
console.log(str2.charAt(4)); // Outputs: 'S'


3. String Properties and Methods:

  • length: Property that returns the length of the string.
  • concat(): Method that concatenates two or more strings and returns a new string.
  • toUpperCase(): Method that converts the string to uppercase.
  • toLowerCase(): Method that converts the string to lowercase.
  • indexOf(): Method that returns the index within the calling String object of the first occurrence of the specified value.
  • slice(): Method that extracts a section of a string and returns it as a new string.
  • substring(): Method that returns the part of the string between the start and end indexes.
  • replace(): Method that replaces a specified value with another value in a string.
  • split(): Method that splits a string into an array of substrings based on a specified separator.

Example Usage:

					const sentence = 'JavaScript is fun!';

console.log(sentence.length); // Outputs: 18
console.log(sentence.concat(' Especially
when you learn it.')); // Outputs: JavaScript is fun! 
Especially when you learn it.
console.log(sentence.toUpperCase()); // Outputs:
console.log(sentence.indexOf('fun')); // Outputs: 11
console.log(sentence.slice(0, 10)); // Outputs: 
console.log(sentence.replace('fun', 'exciting')); 
// Outputs: JavaScript is exciting!
console.log(sentence.split(' ')); // Outputs: 
['JavaScript', 'is', 'fun!']


4. Template Literals:

Template literals, introduced in ECMAScript 6 (ES6), provide an easy way to create strings with placeholders for variables and expressions. They are enclosed in backticks (“) and can span multiple lines:

					const name = 'Alice';
const age = 30;

const message = `Hello, my name is ${name} and
I'm ${age} years old.`;
console.log(message); // Outputs: Hello,
my name is Alice and I'm 30 years old.


Template Strings

  • Templates were introduced with ES6 (JavaScript 2016).
  • Templates are strings enclosed in backticks (`This is a template string`).

  • Templates allow multiline strings:

					let text =
`The quick
brown fox
jumps over
the lazy dog`;