Retrieve the first item in each of the two arrays

Question

Retrieve the first item in each of the two arrays

I have a pair of arrays consisting of objects:

var books = [
  { id: 1, name: 'Book X' },
  { id: 2, name: 'Book Y' }
];

var cars = [
  { id: 1, name: 'Car P' },
  { id: 2, name: 'Car Q' },
  { id: 3, name: 'Car R' },
];

My objective is to generate an array of strings that includes:
1. The title of the first Book in the books array (if available)
2. The titles of the initial 2 Cars in the cars array (if available)

I can achieve this by:

if (books.length > 0)
  var firstBook = books[0].name;

Alternatively:

if (cars.length > 1) {
  var firstCar = cars[0].name;
  var secondCar = cars[1].name;
}

I am open to suggestions for better approaches to accomplish this task.

javascript

Answer 1

Answer №1

Utilizing filter() and map() methods

var fruits = [
  { id: 1, type: 'Apple' },
  { id: 2, type: 'Orange' }
];

var animals = [
  { id: 1, name: 'Dog' },
  { id: 2, name: 'Cat' },
  { id: 3, name: 'Bird' }
];

var result = [fruits[0], animals[0], animals[1]]
     .filter(item => item)// remove any undefined values
     .map(({type:t}) => t)

console.log(result)

Answer 2

Utilizing filter() and map() methods

var fruits = [
  { id: 1, type: 'Apple' },
  { id: 2, type: 'Orange' }
];

var animals = [
  { id: 1, name: 'Dog' },
  { id: 2, name: 'Cat' },
  { id: 3, name: 'Bird' }
];

var result = [fruits[0], animals[0], animals[1]]
     .filter(item => item)// remove any undefined values
     .map(({type:t}) => t)

console.log(result)

Answer 3

Answer №2

To efficiently merge arrays in ES6, you can utilize the spread operator [...array1, ...array2]. In this scenario, I implemented slicing to extract elements from the 'books' and 'cars' arrays while mapping them to a new array with only string names.

var resultArray =[];

var books = [
  { id: 1, name: 'Book A' },
  { id: 2, name: 'Book B' }
];

var cars = [
  { id: 1, name: 'Car A' },
  { id: 2, name: 'Car B' },
  { id: 3, name: 'Car C' }
];

resultArray = [...resultArray, ...books.slice(0,1).map(v => v.name)]

resultArray = [...resultArray, ...cars.slice(0,2).map(v => v.name)]

console.log(resultArray)

Answer 4

To efficiently merge arrays in ES6, you can utilize the spread operator [...array1, ...array2]. In this scenario, I implemented slicing to extract elements from the 'books' and 'cars' arrays while mapping them to a new array with only string names.

var resultArray =[];

var books = [
  { id: 1, name: 'Book A' },
  { id: 2, name: 'Book B' }
];

var cars = [
  { id: 1, name: 'Car A' },
  { id: 2, name: 'Car B' },
  { id: 3, name: 'Car C' }
];

resultArray = [...resultArray, ...books.slice(0,1).map(v => v.name)]

resultArray = [...resultArray, ...cars.slice(0,2).map(v => v.name)]

console.log(resultArray)

Answer 5

Answer №3

This method provides a unique approach to creating a data structure called arrayDefinition. This structure allows you to specify which property to retrieve from different arrays at specific indexes. It can be useful for fetching data from a RESTful webservice, among other things.

var books = [
  { id: 1, name: 'Book A' },
  { id: 2, name: 'Book B' }
];

var cars = [
  { id: 1, name: 'Car A' },
  { id: 2, name: 'Car B' },
  { id: 3, name: 'Car C' },
];

const arrayDefinition = [ 
  { 
    source: 'books', 
    index: 0, 
    prop: 'name'
  },
  { 
    source: 'cars', 
    index: 0, 
    prop: 'name'
  },
  { 
    source: 'cars', 
    index: 1, 
    prop: 'name'
  }
];

let resultArr = []

arrayDefinition.forEach(function(def) {
  if (Array.isArray(window[def.source]) && window[def.source].length >= def.index) {
    resultArr.push(window[def.source][def.index][def.prop])
  }
})

console.log(resultArr)

Answer 6

This method provides a unique approach to creating a data structure called arrayDefinition. This structure allows you to specify which property to retrieve from different arrays at specific indexes. It can be useful for fetching data from a RESTful webservice, among other things.

var books = [
  { id: 1, name: 'Book A' },
  { id: 2, name: 'Book B' }
];

var cars = [
  { id: 1, name: 'Car A' },
  { id: 2, name: 'Car B' },
  { id: 3, name: 'Car C' },
];

const arrayDefinition = [ 
  { 
    source: 'books', 
    index: 0, 
    prop: 'name'
  },
  { 
    source: 'cars', 
    index: 0, 
    prop: 'name'
  },
  { 
    source: 'cars', 
    index: 1, 
    prop: 'name'
  }
];

let resultArr = []

arrayDefinition.forEach(function(def) {
  if (Array.isArray(window[def.source]) && window[def.source].length >= def.index) {
    resultArr.push(window[def.source][def.index][def.prop])
  }
})

console.log(resultArr)

Retrieve the first item in each of the two arrays

Answer №1

Answer №2

Answer №3

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