JavaScript string includes() method

The includes() method in JavaScript is used to determine whether a string contains a specified substring. It returns true if the substring is found within the string, and false otherwise. Here’s the syntax:

string.includes(searchString, position)

• searchString: The substring to search for within the string.
• position (optional): The index at which to start the search within the string. If not specified, the search starts from index 0.

The includes() method is case-sensitive, meaning it distinguishes between uppercase and lowercase characters. Here’s an example:

var str = "Hello, world!";

console.log(str.includes("Hello"));   // true
console.log(str.includes("hello"));   // false (case-sensitive)
console.log(str.includes("world"));   // true
console.log(str.includes("World"));   // false (case-sensitive)
console.log(str.includes("lo"));      // true
console.log(str.includes("lo", 5));   // false (search starts from index 5)

In this example, the includes() method is called on the str string object. It checks whether the specified substrings are present within the string and returns true or false accordingly.