Why does !new Boolean(false) equals false in JavaScript?

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new Boolean(false) returns an object. All objects (except document.all in browsers) are truthy.

As a result, ! of any object will always be false.

To prove it to yourself, you can run this in your JavaScript console:

(typeof new Boolean(false)) // "object"

Also, you can use the strict equality operator === to confirm that new Boolean(false) isn’t really false:

new Boolean(false) === false // false

Incidentally, calling the Boolean function as a function—without the new—actually does return a primitive:

!Boolean(false) // true
(typeof Boolean(false)) // "boolean"

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