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JS Test #1: Type conversion in JavaScript

coderslang profile image Coderslang: Become a Software Engineer Originally published at learn.coderslang.com Updated on ・1 min read

A couple of months back, I've started posting colorful JavaScript code snippets that you can use to check your JS skills on my blog. Every problem has the correct answer and explanation. But I strongly suggest you first try to solve it yourself.

Every day in February I'm going to post a new JS test here on Dev.to. Follow, like, comment if it's something you're interested in.

Let's go 🚀!
js-test
What’s going to be printed to the console?

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In the first line, we define the variable str and initialize it as a string with the value 1.

In the second line, there are two typecasts, first !str gives us false, and then +false converts boolean into a number 0.

Eventually, in the third line, the typeof operator looks up the current type of str which is number.

ANSWER: string number will be printed to the console

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Discussion (1)

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jordanaf808 profile image
jordanaf808

so we go from a string, to a boolean, to a number, wow. :)