A string is a sequence of one or more characters that may consist of letters, numbers, or symbols. Strings in JavaScript are primitive data types and immutable, which means they are unchanging.

String Methods & Properties in JavaScript

In JavaScript, strings are primitive data types, and they come with several methods and properties that allow you to manipulate, query, and transform them. Here's a comprehensive overview:

String Properties

1. length:

   • Description: Returns the number of characters in a string.

   • Example:

     let str = "Hello, World!";
     console.log(str.length);  // Output: 13
     
     

String Methods

1. charAt(index):

   • Description: Returns the character at a specified index.

   • Example:

     let str = "Hello";
     console.log(str.charAt(1));  // Output: "e"
     
     

2. charCodeAt(index):

   • Description: Returns the Unicode value (character code) of the character at the specified index.

   • Example:

     let str = "Hello";
     console.log(str.charCodeAt(1));  // Output: 101 (Unicode value of "e")
     
     

3. concat(str2, str3, ...):

   • Description: Combines multiple strings into one.

   • Example:

     let str1 = "Hello";
     let str2 = " World!";
     console.log(str1.concat(str2));  // Output: "Hello World!"
     
     

4. includes(searchString):

   • Description: Returns true if the string contains the specified substring, otherwise false.

   • Example:

     let str = "Hello, World!";
     console.log(str.includes("World"));  // Output: true
     
     

5. indexOf(searchString):

   • Description: Returns the first index at which the specified substring is found, or 1 if not found.

   • Example:

     let str = "Hello, World!";
     console.log(str.indexOf("World"));  // Output: 7
     
     

6. replace(searchValue, newValue):

   • Description: Replaces the first occurrence of a substring with a new substring.

   • Example:

     let str = "Hello, World!";
     console.log(str.replace("World", "JavaScript"));  // Output: "Hello, JavaScript!"
     
     

7. slice(start, end):

   • Description: Extracts a portion of a string from the start index up to (but not including) the end index.

   • Example:

     let str = "Hello, World!";
     console.log(str.slice(7, 12));  // Output: "World"
     
     

8. split(separator):

   • Description: Splits a string into an array of substrings based on the specified separator.

   • Example:

     let str = "apple,banana,orange";
     let fruits = str.split(",");
     console.log(fruits);  // Output: ["apple", "banana", "orange"]
     
     

9. toLowerCase():

   • Description: Converts all characters in the string to lowercase.

   • Example:

     let str = "HELLO";
     console.log(str.toLowerCase());  // Output: "hello"
     
     

10. toUpperCase():

    • Description: Converts all characters in the string to uppercase.

    • Example:

      let str = "hello";
      console.log(str.toUpperCase());  // Output: "HELLO"
      
      

11. trim():

    • Description: Removes whitespace from both ends of the string.

    • Example:

      let str = "   Hello, World!   ";
      console.log(str.trim());  // Output: "Hello, World!"
      
      

12. startsWith(searchString):

    • Description: Checks if the string starts with the specified substring, returns true or false.

    • Example:

      let str = "Hello, World!";
      console.log(str.startsWith("Hello"));  // Output: true