isNaN
INFO
This function is only available in es-toolkit/compat for compatibility reasons. It either has alternative native JavaScript APIs or isn’t fully optimized yet.
When imported from es-toolkit/compat, it behaves exactly like lodash and provides the same functionalities, as detailed here.
Check if the given value is NaN.
This function can also serve as a type predicate in TypeScript, narrowing the type of the argument to NaN.
Signature
typescript
function isNaN(value: unknown): value is typeof NaN;Parameters
value(unknown): The value to test if it is NaN.
Returns
(value is typeof NaN): True if the value is NaN, otherwise false.
Examples
typescript
const value1 = NaN;
const value2 = undefined;
console.log(isNaN(value1)); // true
console.log(isNaN(value2)); // false