JavaScript String includes function

String includes is a function introduced to JavaScript in Escmascript 'es6' that returns a boolean true , or false based on the evaluation whether or not a string contains the string passed as an argument to the function

For example;

const str = "John swana"
str.includes('John')
// true

str.includes('duke')
// false

Running string includes testing whether 'John swana' includes John returns trues as it's a fact.

Running the same string against duke returns false duke is not part of the string 'str'