Take a look at the below code: const day = 'monday' if(day = 'monday' || day = 'tuesday' || day = 'wednesday') The includes method also comes in handy when comparing with different values. So using the Array includes methods makes code short and easy to understand. The same code using the Array includes method can be written as shown below: // ES7 Code const numbers = console.log(numbers.includes('one')) // true console.log(numbers.includes('five')) // false ES5 Code const numbers = console.log(numbers.indexOf('one') > -1) // true console.log(numbers.indexOf('five') > -1) // false ĮS7 has added this function that checks if an element is present in the array or not and returns a boolean value of either true or false. There is a lot more covered in the actual book.Ĭheck out my previous post to get more preview content if you missed it. Note: This is the final short preview of content from Mastering Modern JavaScript book.

So let’s look at some of the things added in JavaScript which you need to be familiar with to improve your skills and get a high paying job. And these updates are very useful if you want to improve your coding skills. Over the past few years, there have been many updates to the JavaScript language.

Array includes javascript