A guide to extracting distinct values from an array of objects by a specified key in Javascript using ES5

Question

A guide to extracting distinct values from an array of objects by a specified key in Javascript using ES5

This particular post on Stack Overflow discusses a method for retrieving all distinct values from a JavaScript array by eliminating duplicates. One of the answers presents this solution using ES6 syntax, which utilizes arrow functions and spread operators. However, I am seeking assistance in converting this code to ES5 without the use of arrows or ellipses.

var objArr = [{
  id: '123'
}, {
  id: '123'
}, {
  id: '456'
}];

objArr = objArr.reduce(function(acc, cur) {
  return acc.filter(function(obj) {
    return obj.id !== cur.id;
  }).concat(cur);
}, []);

console.log(objArr);

javascript arrays

Answer 1

Answer №1

Hopefully this solution proves useful.

const objectArray = [{
  id: '100'
}, {
  id: '200'
}, {
  id: '300'
}];

const newObjectArray = objectArray.reduce((prev, curr) => {
    const exists = prev.filter(item => item.id === curr.id).length > 0;
    if(!exists){
        prev.push(curr);
    }
    return prev;
}, []);

console.log(newObjectArray);

Answer 2

Hopefully this solution proves useful.

const objectArray = [{
  id: '100'
}, {
  id: '200'
}, {
  id: '300'
}];

const newObjectArray = objectArray.reduce((prev, curr) => {
    const exists = prev.filter(item => item.id === curr.id).length > 0;
    if(!exists){
        prev.push(curr);
    }
    return prev;
}, []);

console.log(newObjectArray);

Answer 3

Answer №2

const objectsArr = [{ id: '123' }, { id: '123' }, { id: '456' }]

objectsArr = objectsArr.reduce(function (accumulator, current) {
    return accumulator.filter(function (object) {
        return object.id !== current.id
    }).concat([current])
}, [])

console.log(objectsArr)

Answer 4

const objectsArr = [{ id: '123' }, { id: '123' }, { id: '456' }]

objectsArr = objectsArr.reduce(function (accumulator, current) {
    return accumulator.filter(function (object) {
        return object.id !== current.id
    }).concat([current])
}, [])

console.log(objectsArr)

Answer 5

Answer №3

To efficiently remove duplicates from an array of objects, you can utilize the reduce method and map function:

let unique = objArr.reduce(function(acc, curr){
    acc[curr.id] = acc[curr.id] || {};
    acc[curr.id] = curr.id;
    return acc;
},{})

console.log(Object.values(unique).map(function(item){return {id: item}}))

Let's consider the following example:

let objArr = [{
  id: '123'
}, {
  id: '123'
}, {
  id: '456'
}];

let unique = objArr.reduce(function(acc, curr){
acc[curr.id] = acc[curr.id] || {};
    acc[curr.id] = curr.id;
return acc;
},{})

console.log(Object.values(unique).map(function(item){return {id: item}}))

Answer 6

To efficiently remove duplicates from an array of objects, you can utilize the reduce method and map function:

let unique = objArr.reduce(function(acc, curr){
    acc[curr.id] = acc[curr.id] || {};
    acc[curr.id] = curr.id;
    return acc;
},{})

console.log(Object.values(unique).map(function(item){return {id: item}}))

Let's consider the following example:

let objArr = [{
  id: '123'
}, {
  id: '123'
}, {
  id: '456'
}];

let unique = objArr.reduce(function(acc, curr){
acc[curr.id] = acc[curr.id] || {};
    acc[curr.id] = curr.id;
return acc;
},{})

console.log(Object.values(unique).map(function(item){return {id: item}}))

A guide to extracting distinct values from an array of objects by a specified key in Javascript using ES5

Answer №1

Answer №2

Answer №3

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