Cerebrum

String Methods

3 min read

1. IndexOf()
2. charCodeAt()
3. includes()
4. slice()
5. toUpperCase()
6. toLowerCase()
7. replace()
8. repeat()
9. trim()
10. trimStart()
11. trimEnd()
12. prompt()
  • The indexOf Method: This method is used to search for a substring within a string. If the substring is found, indexOf returns the index (or position) of the first occurrence of that substring. If the substring is not found, indexOf returns -1, which indicates that the search was unsuccessful.
const text = "The quick brown fox jumps over the lazy dog.";
console.log(text.indexOf("fox")); // 16
console.log(text.indexOf("cat")); // -1
  • The includes() Method: This method is used to check if a string contains a specific substring. If the substring is found within the string, the method returns true. Otherwise, it returns false. its a case sensitive method
const text = "The quick brown fox jumps over the lazy dog.";
console.log(text.includes("fox")); // true
console.log(text.includes("cat")); // false

You can also use the includes() method to check for a substring starting at a specific index in the string by providing a second parameter:

  • The  slice() Method: This method extracts a portion of a string and returns a new string, without modifying the original string. It takes two parameters: the starting index and the optional ending index.

  • The toUpperCase() & toLoweCase() Method:

const text = "Hello, world!";
console.log(text.toUpperCase()); // "HELLO, WORLD!"
const text = "HELLO, WORLD!"
console.log(text.toLowerCase()); // "hello, world!"
  • The replace() Method: This method is used to find a specified value (like a word or character) in a string and replace it with another value.
const text = "I like cats";
console.log(text.replace("cats", "dogs")); // "I like dogs"
  • The repeat() Method: This method is used to repeat a string a specified number of times.
const text = "Hello";
console.log(text.repeat(3)); // "HelloHelloHello"
  • The trim() Method: This method is used to remove whitespaces from both the beginning and the end of a string.
const text = "  Hello, world!  ";
console.log(text.trim()); // "Hello, world!"
  • The trimStart() Method: This method removes whitespaces from the beginning (or “start”) of the string.
const text = "  Hello, world!  ";
console.log(text.trimStart()); // "Hello, world!  "
  • The trimEnd() Method: This method removes whitespaces from the end of the string.
const text = " Hello, world! ";
console.log(text.trimEnd()); // "  Hello, world!"
  • The prompt() Method 1: This method of the window is used to get information from a user through the form of a dialog box. This method takes two arguments. The first argument is the message which will appear inside the dialog box, typically prompting the user to enter information. The second one is a default value which is optional and will fill the input field initially.
const answer = window.prompt("What's your favorite animal?"); // This will change depend

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