function isGeneratorFunction
Usage in Deno
```typescript import { isGeneratorFunction } from "node:node__util--types.d.ts"; ```
isGeneratorFunction(object: unknown): object is GeneratorFunction
Returns `true` if the value is a generator function.
This only reports back what the JavaScript engine is seeing;
in particular, the return value may not match the original source code if
a transpilation tool was used.
```js
util.types.isGeneratorFunction(function foo() {}); // Returns false
util.types.isGeneratorFunction(function* foo() {}); // Returns true
```
object is GeneratorFunction