JavaScript Truthy vs Falsy: Why {}, [], and Even new Boolean(false) Are Truthy? Confused by JavaScript Booleans? Here's Why Boolean({}) and Boolean([]) Return True.

Our code :-

console.log(Boolean({}));
console.log(Boolean([]));
console.log(Boolean(""));
Boolean(new Boolean(false));

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Line 1: console.log(Boolean({}))

What's Happening?

• {} is an empty object.

In JavaScript:

• All objects are truthy, even empty ones.
• Boolean({}) → true

Output: true

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Line 2: console.log(Boolean([]))

What's Happening?

• [] is an empty array, which is also an object.

Again:

• All objects are truthy, including arrays (even empty ones).
• Boolean([]) → true

Output: true

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Line 3: console.log(Boolean(""))

What's Happening?

• "" is an empty string, which is one of the falsy primitive values in JavaScript.

List of falsy values includes:

• false, 0, "", null, undefined, NaN

So:

• Boolean("") → false

Output: false

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Line 4: Boolean(new Boolean(false))

This is super tricky and often misunderstood.

What’s going on?

• new Boolean(false) creates a Boolean object, not a primitive.
• It wraps the value false, but it's still an object.

Remember:

All objects are truthy, even if they represent a falsy value.

So:

Boolean(new Boolean(false)) → true

💡 Note: This line does not log anything because it’s not inside console.log(), but the value is true.

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Key points :-

• Primitive false is falsy, but new Boolean(false) is an object, which is truthy.
• Avoid new Boolean(), new String(), and new Number() — they create wrapper objects that can lead to unexpected behavior.
• Use Boolean(value) or !!value to test truthiness reliably.

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✔ Final Answer:

true // Line 1

true // Line 2 false // Line 3 // Line 4 does nothing visible, but returns true

B) true true false true

NOTE :- when we run our code on browser console, we got above output where below code print true.

Boolean(new Boolean(false));

This question appeared in the Publicis Sapient 2nd round of interview, testing the candidate’s knowledge of type coercion in JavaScript.