What are falsy values in JavaScript?

The falsy values in JavaScript are 0, 0n, null, undefined, false, NaN, and the empty string "". They evaluate to false when coerced by JavaScript’s typing engine into a boolean value, but they are not necessarily equal to each other.

Photo by Matej Drha on Unsplash

Falsy values in JavaScript

“A falsy value is a value that is considered false when encountered in a Boolean context.” — Mozilla Developer Network

In JavaScript, there is a special list of following 7 values, which are called falsy values — they all evaluate to false in conditionals:

• the number 0. (and -0)
• the BigInt 0n
• the keyword null
• the keyword undefined
• the boolean false
• the number NaN
• the empty string "" (equivalent to '' or ``)

Strictly speaking, you have to “coerce” (force) a falsy value to make it false, for example by using Boolean() or the ? ternary operator.