index02.js

index02.js

const products = [
  {id: 1, price: 10}, {id: 2, price: 11}, {id: 3, price: 1},
  {id: 4, price: 3}, {id: 5, price: 1}, {id: 6, price: 8},
  {id: 7, price: 3}, {id: 8, price: 0}, {id: 9, price: 4},
  {id: 10, price: 5}, {id: 11, price: 9}, {id: 12, price: 13},
];

const getFirstItems = (products, size) => {
  return products.slice(0, size)
}

const getLastItems = (products, size) => {
  const toSplice = (size * 2 > products.length) ?
    products.length - size : size

  if (toSplice <= 0) {
    return null
  }

  return products.slice(-(toSplice))
}

const getHighestAndLowestItems = (products, size) => {
  if (size > products.length || size === 0) {
    return {
      highest: null,
      lowest: null,
    }
  }

  return {
    highest: getFirstItems(products, size),
    lowest: getLastItems(products, size)
  }
}

const sortItems = (products) => {
  return products.sort((a, b) => {
    if (a.price < b.price) {
      return 1
    }
    
    if (b.price < a.price) {
      return -1
    }
    
    return 0
  })
}

/**
* @params [Array] products - list of products
* @params [Number] options.size - Optional parameter. By default it should be 5
**/
function sortProducts(products, options = { size: 5 }) {
  const size = options.size >= 0 ? options.size : 5

  return getHighestAndLowestItems(sortItems(products), size)
}

// Sorry guys, don't have much time left to write real world Unit tests :(
// toEql (jest)
expect(sortProducts(products)).toEql(expectedResult) // {highest: Array(5), lowest: Array(5)}
expect(sortProducts(products, { size: 0 })).toEql(expectedResult) // {highest: null, lowest: null}
expect(sortProducts(products, { size: -10 })).toEql(expectedResult) // {highest: Array(5), lowest: Array(5)}
expect(sortProducts(products, { size: 10 })).toEql(expectedResult) // {highest: Array(10), lowest: Array(2)}
expect(sortProducts(products, { size: 12 })).toEql(expectedResult) // {highest: Array(12), lowest: null}
expect(sortProducts(products, { size: 13 })).toEql(expectedResult) // {highest: null, lowest: null}