What are truthy and falsy values in JavaScript?

Question

What are truthy and falsy values in JavaScript?

Answer

Every value in JavaScript is either truthy or falsy when evaluated in a Boolean context.

Falsy values:
false, 0, -0, "", null, undefined, NaN

Everything else is truthy.

if ('') console.log('Truthy');
else console.log('Falsy'); // Falsy

Truthy values are all non-falsy ones, like "hello", 42, {}, and [].

Real-World Example

Falsy values are often used in condition checks:

const user = '';
if (!user) {
  console.log('No user logged in');
}

Quick Practice

Write a function that checks if a value is truthy or falsy using a simple conditional.

Summary

Knowing what’s truthy or falsy helps you write cleaner, bug-free conditionals.