JavaScript Interview Question #40: What is the type of `undefined` in JS?

What’s the output?

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In JavaScript, the typeof operator always returns a string.

So, even though typeof undefined evaluates to undefined, it’s a string and not the primitive undefined value.

The str…


This content originally appeared on DEV Community and was authored by Coderslang: Become a Software Engineer

js-test-40

What's the output?

.

.

.

.

.

.

.

.

.

.

.

.

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.

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In JavaScript, the typeof operator always returns a string.

So, even though typeof undefined evaluates to undefined, it’s a string and not the primitive undefined value.

The string ’undefined’ is not equal to the value undefined.

ANSWER: the message false will appear in the console.

Learn Full-Stack JavaScript


This content originally appeared on DEV Community and was authored by Coderslang: Become a Software Engineer


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