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isUndefined - node__util.d.ts - Node documentation
function isUndefined

Usage in Deno

```typescript import { isUndefined } from "node:node__util.d.ts"; ```
isUndefined(object: unknown): object is undefined
Deprecated
Since v4.0.0 - Use `value === undefined` instead.
Returns `true` if the given `object` is `undefined`. Otherwise, returns `false`. ```js import util from 'node:util'; const foo = undefined; util.isUndefined(5); // Returns: false util.isUndefined(foo); // Returns: true util.isUndefined(null); // Returns: false ```

Parameters

object: unknown

Return Type

object is undefined