## Manipulate Keys
### Instructions
I do not want onions. I want oranges.
Create 3 functions that works like the `.filter` , `.map` and `.reduce` array methods, but for the **keys** of your grocery cart. You can see their names and how they work in the examples.
### Examples
```js
const nutrients = { carbohydrates: 12, protein: 20, fat: 5 }
console.log(filterKeys(nutrients, (key) => /protein/.test(key)))
// output: { protein: 20 }
console.log(mapKeys(nutrients, (k) => `-${k}` ))
// output: { -carbohydrates: 12, -protein: 20, -fat: 5 }
console.log(reduceKeys(nutrients, (acc, cr) =>acc.concat(', ', cr)))
// output: carbohydrates, protein, fat
```
### Code provided
> The provided code will be added to your solution, and does not need to be submitted.
```js
// small database with nutrition facts, per 100 grams
// prettier-ignore
const nutritionDB = {
tomato: { calories: 18, protein: 0.9, carbs: 3.9, sugar: 2.6, fiber: 1.2, fat: 0.2 },
vinegar: { calories: 20, protein: 0.04, carbs: 0.6, sugar: 0.4, fiber: 0, fat: 0 },
oil: { calories: 48, protein: 0, carbs: 0, sugar: 123, fiber: 0, fat: 151 },
onion: { calories: 0, protein: 1, carbs: 9, sugar: 0, fiber: 0, fat: 0 },
garlic: { calories: 149, protein: 6.4, carbs: 33, sugar: 1, fiber: 2.1, fat: 0.5 },
paprika: { calories: 282, protein: 14.14, carbs: 53.99, sugar: 1, fiber: 0, fat: 12.89 },
sugar: { calories: 387, protein: 0, carbs: 100, sugar: 100, fiber: 0, fat: 0 },
orange: { calories: 49, protein: 0.9, carbs: 13, sugar: 12, fiber: 0.2, fat: 0.1 },
}
```
### Notions
- [filter ](https://devdocs.io/javascript/global_objects/array/filter )
- [map ](https://devdocs.io/javascript/global_objects/array/map )
- [reduce ](https://devdocs.io/javascript/global_objects/array/reduce )
- [entries ](https://devdocs.io/javascript/global_objects/object/entries )
- [fromEntries ](https://devdocs.io/javascript/global_objects/object/fromentries )
