Merge 2 arrays of objects based on different key but same value

Question

I have referred questions listed below, but got not related answer.

I have 2 arrays of objects,

OBJ1 -

[
    {
        "ID": 58895,
        "step": "Outage Agreed w/ Business"
    },
    {
        "ID": 58896,
        "step": "GMLC/E911/CMAS Significant"
    }
]

OBJ2 -

[
    {
        "type": "verification_step",
        "value": "GMLC/E911/CMAS Significant"
    },
    {
        "type": "verification_step",
        "value": "Outage Agreed w/ Business"
    }
]

I want to have the output which contains the both values in the single object based on the value of the string i.e.

[
    {
        "ID": 58896,
        "type": "verification_step",
        "step": "GMLC/E911/CMAS Significant"
    },
    {
        "ID": 58895,
        "type": "verification_step",
        "step": "Outage Agreed w/ Business"
    }
]

Please suggest me the way out. (ES6 solution - much appreciated)

Edit

The 3rd reference which have assiged as duplicate is not the scenario. The key should remain "step" and the data should be merged.

Possible duplicate of [Merge two array of objects based on a key](https://stackoverflow.com/questions/46849286/merge-two-array-of-objects-based-on-a-key) — hindmost, Jun 04 '19 at 16:13
OBJ1.map(item => ({ ...item, type: OBJ2.find(item2 => item2.value === item.step).type, })) — Zaptree, Jun 04 '19 at 16:24

Maheer Ali · Accepted Answer · 2019-06-04T16:22:43.557

2

You can use reduce() after combining both the arrays.

const arr1 = [ { "ID": 58895, "step": "Outage Agreed w/ Business" }, { "ID": 58896, "step": "GMLC/E911/CMAS Significant" } ] 

const arr2 = [ { "type": "verification_step", "value": "GMLC/E911/CMAS Significant" }, { "type": "verification_step", "value": "Outage Agreed w/ Business" } ]

const res = [...arr1,...arr2.map(({value,...rest}) => ({step:value,...rest}))].reduce((ac,a) => {
  let k = a.step;
  ac[k] = {...ac[k],...a} || a;
  return ac;
},{})
console.log(Object.values(res))

edited Jun 04 '19 at 16:22

answered Jun 04 '19 at 16:13

Maheer Ali

35,834
5
42
73

Is that possible that the key remain to be "step" instead of "value"? – Keyur Jun 04 '19 at 16:15
@KeyurK Please add the expected ouput. – Maheer Ali Jun 04 '19 at 16:15
Edited the expected output – Keyur Jun 04 '19 at 16:19
This is not I wanted Maheer. I want to compare the string and then merge the data. I have not only ID to be merged. – Keyur Jun 04 '19 at 16:31
@KeyurK I know that. It will work for more properties. My gives the correct output i guess that you have posted. Can you please tell where it fails? – Maheer Ali Jun 04 '19 at 16:36

score 2 · Answer 2 · answered Jun 04 '19 at 16:24

You can probably do this as a one liner, but for readability and efficiency it might be nicer to make a lookup object based on the value you want from one of the arrays and then map the other other array using the lookup to join the other value you want. Something like:

let arr1 = [{"ID": 58895,"step": "Outage Agreed w/ Business"},{"ID": 58896,"step": "GMLC/E911/CMAS Significant"}]
let arr2 = [{"type": "verification_step","value": "GMLC/E911/CMAS Significant"},{"type": "verification_step","value": "Outage Agreed w/ Business"}]

// lookup based on value
let lookup = arr2.reduce((m, {type, value}) => m.set(value, {type}), new Map)

// merge each item based on lookup
let result = arr1.map(item =>  Object.assign({}, item, lookup.get(item.step)))

console.log(result)

score 1 · Answer 3 · answered Aug 12 '20 at 06:35

You can use lodash:

const _ = require('lodash');
const arr1 = [
    {
        "ID": 58895,
        "step": "Outage Agreed w/ Business"
    },
    {
        "ID": 58896,
        "step": "GMLC/E911/CMAS Significant"
    }
]

const arr2 = [
    {
        "type": "verification_step",
        "value": "GMLC/E911/CMAS Significant"
    },
    {
        "type": "verification_step",
        "value": "Outage Agreed w/ Business"
    }
]
const res =  _(arr1)
    .keyBy('step')
    .merge((_.keyBy(arr2, 'value')))
    .values()
    .map((value) => {
      const { ID, type, step } = value
      return {
         ID, 
         type, 
         step
      }
    })
    .value()

Martin Chuka · Answer 4 · 2019-06-04T16:25:53.567

Since you need ES6, you can just use the map operator and concatenate the missing value to just on object. like this

let obj=[
    {
        "type": "verification_step",
        "value": "GMLC/E911/CMAS Significant"
    },
    {
        "type": "verification_step",
        "value": "Outage Agreed w/ Business"
    }
]

const obj1=[
    {
        "ID": 58895,
        "step": "Outage Agreed w/ Business"
    },
    {
        "ID": 58896,
        "step": "GMLC/E911/CMAS Significant"
    }
]


obj.map((ob)=>{
    const found=obj1.find((e)=>{
        return e.step===ob.value;
    });
    if(found){
        ob.ID=found.ID
    }
});

There might be a typo, i just typed it but you get the idea. You need to do necessary check to avoid undefined.

score 0 · Answer 5 · answered Jun 04 '19 at 16:22

0

you can just write Here's the link for testing online es6 compiler

let arr = [];
 obj1.map((val, index) => {
  if(obj2[index]) {
   arr.push({ id: val.ID, type: obj2[index].type, value: obj2[index].value })
  }
});

console.log(arr);

answered Jun 04 '19 at 16:22

Mohammad Quanit

120
2
14

score 0 · Answer 6 · answered Jun 04 '19 at 16:42

You could take a Map for ID and get this value for mapping new objects.

var array1 = [{ ID: 58895, step: "Outage Agreed w/ Business" }, { ID: 58896, step: "GMLC/E911/CMAS Significant" }],
    array2 = [{ type: "verification_step", value: "GMLC/E911/CMAS Significant" }, { type: "verification_step", value: "Outage Agreed w/ Business" }],
    map = new Map(array1.map(({ ID, step }) => [step, ID])),
    result = array2.map(({ type, value: step }) => ({ ID: map.get(step), type, step }));

console.log(result);

Merge 2 arrays of objects based on different key but same value

6 Answers6