## Is

### Instructions

Add new function properties to the object `is`` to check a value type
- `is.num` value is a number
- `is.nan` value is NaN
- `is.str` value is a string
- `is.bool` value is a boolean
- `is.undef` value is undefined
- `is.def` value is defined
- `is.arr` value is an array
- `is.obj` value is a simple object or null objects
- `is.fun` value is a function
- `is.truthy` value is truthy
- `is.falsy` value is falsy


### Notions

- [https://nan-academy.github.io/js-training/examples/primitive-and-operators](https://nan-academy.github.io/js-training/examples/primitive-and-operators)
- [https://devdocs.io/javascript/operators/typeof](https://devdocs.io/javascript/operators/typeof)
- [https://developer.mozilla.org/en-US/docs/Glossary/Truthy](https://developer.mozilla.org/en-US/docs/Glossary/Truthy)
- [https://developer.mozilla.org/en-US/docs/Glossary/Falsy](https://developer.mozilla.org/en-US/docs/Glossary/Falsy)


### Code provided
```js
const is = {}
```