How to use indexOf method in JavaScript

  • In JavaScript indexOf method is used to get the index of the first occurrence of the search value in the string.
  • The indexOf method returns -1 if the search value is not found.
  • The indexOf method is case sensitive.


const welcome = "I see what's happening here"

console.log(welcome.indexOf('happening')) //  13

console.log(welcome.indexOf('I'))  // 0

console.log(welcome.indexOf('hey')) // -1

case sensitive example

console.log("Clap along".indexOf('clap')) //  -1