Is there a cleaner way to add a new property with unique values to an array-CodePudding

I'm just learning js now (late to the party I know) and I have the following code and I was wondering if it could be written in a cleaner/simpler way?

Also, ideally, instead of using "if (obj.id === 1)" I would like to iterate through the array and add age based on the sequence i.e. [0] would become '32' and so on.

const students = [ // Three objects, each with four properties
 {
  id: 1,
  name: 'Mark',
  profession: 'Developer',
  skill: 'JavaScript'
 },
 {
  id: 2,
  name: 'Ariel',
  profession: 'Developer',
  skill: 'HTML'
 },
 {
  id: 3,
  name: 'Jason',
  profession: 'Designer',
  skill: 'CSS'
 },
];

const studentsWithAge = students.map(obj => {
if (obj.id === 1) {
 return {...obj, age: '32'};
 } else if (obj.id === 2) {
  return {...obj, age: '26'};
 } else if (obj.id === 3) {
  return {...obj, age: '28'};
 }
 return obj;
});

console.log(studentsWithAge);

// output
// [
//  {
//   id: 1,
//   name: 'Mark',
//   profession: 'Developer',
//   skill: 'JavaScript',
//   age: '32'
//  },
//  {
//   id: 2,
//   name: 'Ariel',
//   profession: 'Developer',
//   skill: 'HTML',
//   age: '26'
//  },
//  {
//   id: 3,
//   name: 'Jason',
//   profession: 'Designer',
//   skill: 'CSS',
//   age: '28'
//  }
// ]

CodePudding user response：

You can map the array into the object like so:

const ages = ['32', '26', '28'];
const studentsWithAge = students.map(obj => { ...obj, age: ages[obj.id-1] });

CodePudding user response：

You could create an ages array and use the index to map the value to the corresponding object.

const students = [ // Three objects, each with four properties
  {
    id: 1,
    name: 'Mark',
    profession: 'Developer',
    skill: 'JavaScript'
  },
  {
    id: 2,
    name: 'Ariel',
    profession: 'Developer',
    skill: 'HTML'
  },
  {
    id: 3,
    name: 'Jason',
    profession: 'Designer',
    skill: 'CSS'
  },
];

const ages = [32, 26, 28];

const result = students.map((s, i) => {
  return { ...s, age: ages[i] }
});

console.log(result);

CodePudding user response：

Your code is true, another way to add ages by the id is the following code. Just use ids as object key and age as value.

The following code check if id exists in the ages const then add it to the studentsWithAge. It works exactly like your code.

const ages = {1: '32', 2: '26', 3: '28'};

const studentsWithAge = students.map(obj => { 
    if(ages[obj.id]) obj.age = ages[obj.id]; 
    return obj;
});

But if you're sure all ids have age value simpler code like this could be used:

const ages = {1: '32', 2: '26', 3: '28'};
const studentsWithAge = students.map(obj => ({...obj, age: ages[obj.id]}));