What is the Return Value of typeof typeof 1?

What is the Return Value of typeof typeof 1?

Ferenc Almasi β€’ 2020 December 10 β€’ Read time 1 min read
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JavaScript

Do you know, what is the return value of the following JavaScript expression?

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typeof typeof 1
typeof.js

If you've guessed it was "string", then you were right. Let's take it apart to see why is that. The code above can be rewritten as:

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typeof (typeof 1)
typeof.js

This can be broken down, further into two pieces:

  • typeof 1
  • typeof (<the return value of typeof 1>)
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// This will return "number"
typeof 1
typeof.js

The first part will return "number", and it's type is a string:

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// This will return "string"
typeof "number"
typeof.js

This means, that typeof typeof 1 will return "string".

What is the return value of typeof typeof 1 in JavaScript?
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