Merge / Replace object in array with same Id

Question

I have 2 arrays, and I try to merge the 2 arrays based on their id, and the sequence of the array must be same as the first array

array1: [
{id: student1, name: 'Jacky', course: ''},
{id: student2, name: 'Taylor', course: ''},
{id: student3, name: 'David', course: ''},
{id: student4, name: 'Aisy', course: ''},
{id: student5, name: 'Micky', course: ''}
];

and

array2: [
{id: student1, name: 'Jacky', course: 'science'},
{id: student2, name: 'Taylor', course: 'biology'},
{id: student1, name: 'Jacky', course: 'math'},
{id: student4, name: 'Aisy', course: 'chemistry'},
{id: student1, name: 'Jacky', course: 'history'},
];

I want the result be like

array:[
{id: student1, name: 'Jacky', course: 'science'},
{id: student1, name: 'Jacky', course: 'math'},
{id: student1, name: 'Jacky', course: 'history'},
{id: student2, name: 'Taylor', course: 'biology'},
{id: student3, name: 'David', course: ''},
{id: student4, name: 'Aisy', course: 'chemistry'},
{id: student5, name: 'Micky', course: ''}
];

Does this answer your question? Merge and sort two object arrays in Javascript — Vikas
– Vikas, Commented Jan 28, 2020 at 8:40
Can the first array contain duplicates? Can the second array contain IDs which are not in the first array? Please add constraints, if any, without which, this question is too broad to answer. And most important, please add what you've already tried. — 31piy
– 31piy, Commented Jan 28, 2020 at 8:46
@31piy, yes, the first array can contain duplicates like the second array Jacky's records, second array will not contain id which not in first array — Lynn
– Lynn, Commented Jan 28, 2020 at 9:21

Smit Vora · Accepted Answer · 2020-01-28 08:49:15Z

3

you can do something like this:

    const result = [];
    array1.forEach(a1 => {
      result.push(a1);
      array2.forEach(a2 => {
        if (a1.id === a2.id) {
          result.push(a2);
        }
      });
    });

or just one line code:

const result =([...array1,...array2]).sort((a, b) => a.id - b.id);

edited Jan 28, 2020 at 8:49

answered Jan 28, 2020 at 8:43

Smit Vora

4703 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Lynn · Accepted Answer · 2020-02-06 07:45:09Z

1

Last based on the reference from above, I found a way thats works for my situation

let _newArray = [];
    array1.forEach(element => {
      const temp = array2.filter(x => x.id === element.id);
      const temp2 = temp.filter(
        x => !_newArray.find(y => y.id === x.id && y.name === x.name)
      );
      if (temp.length > 0) {
        _newArray = [..._newArray, ...temp2];
      } else {
        _newArray.push(element);
      }
    });

console.log(_newArray);

answered Feb 6, 2020 at 7:45

Lynn

1922 silver badges11 bronze badges

Comments

Nimatullah Razmjo · Accepted Answer · 2020-01-28 09:27:09Z

0

You may need to use spread, filter and forEach feature.

    let array1 = [
    {id: 1, name: 'Jacky', course: ''},
    {id: 2, name: 'Taylor', course: ''},
    {id: 3, name: 'David', course: ''},
    {id: 4, name: 'Aisy', course: ''},
    {id: 5, name: 'Micky', course: ''}
    ]

    let array2 = [
    {id: 1, name: 'Jacky', course: 'science'},
    {id: 2, name: 'Taylor', course: 'biology'},
    {id: 1, name: 'Jacky', course: 'math'},
    {id: 4, name: 'Aisy', course: 'chemistry'},
    {id: 1, name: 'Jacky', course: 'history'},
    ]

    let r = [];
    array1.forEach(course => {
      let arr = array2.filter(c => c.name === course.name);
      if (arr.length > 0) {
    	r = [...r, ...arr];
      } else {
        r.push(course)
      }
    });
    console.log(r);

edited Jan 28, 2020 at 9:27

answered Jan 28, 2020 at 9:21

Nimatullah Razmjo

1,9615 gold badges23 silver badges42 bronze badges

Comments

Mihai Alexandru-Ionut · Accepted Answer · 2020-01-28 12:19:41Z

0

You could use reduce, filter methods in combination with spread syntax.

var array1 = [ {id: 1, name: 'Jacky', course: ''}, {id: 2, name: 'Taylor', course: ''}, {id: 3, name: 'David', course: ''}, {id: 4, name: 'Aisy', course: ''}, {id: 5, name: 'Micky', course: ''} ], array2= [ {id: 1, name: 'Jacky', course: 'science'}, {id: 2, name: 'Taylor', course: 'biology'}, {id: 1, name: 'Jacky', course: 'math'}, {id: 4, name: 'Aisy', course: 'chemistry'}, {id: 1, name: 'Jacky', course: 'history'}, ];
let arr = array1.reduce((arr, item) => {
  let itemsFromSecondArray = array2.filter(({id}) => id == item.id);
  if(itemsFromSecondArray.length){
    arr.push(...itemsFromSecondArray);
  } else arr.push(item);
  return arr;
}, []);
console.log(arr);

edited Jan 28, 2020 at 12:19

answered Jan 28, 2020 at 8:45

Mihai Alexandru-Ionut

48.6k14 gold badges106 silver badges132 bronze badges

Collectives™ on Stack Overflow

Merge / Replace object in array with same Id

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

Comments

Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related