public/subjects/manipulate-keys

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

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.

// 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
• map
• reduce
• entries
• fromEntries