check for character in string javascript code example

Example 1: js string contains

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);

Example 2: javascript includes

const pets = ['cat', 'dog', 'bat'];

console.log(pets.includes('cat'));
// output: true

Example 3: .includes javascript

let storyWords = ['extremely literally actually hi bye okay']
let unnecessaryWords = ['extremely', 'literally', 'actually' ];

let betterWords = storyWords.filter(function(word) {
  return !unnecessaryWords.includes(word);
});
console.log(betterWords) // ['hi' 'bye' 'okay]