How to convert array of objects to single object which has dynamic key in typescript

Question

This question might be similar to frequently asked one, but this one has some different approach.

In my angular 7 application, I have the following 5 arrays which needs to be converted to the below single object with dynamic key based on the id.

{
  "enabled-41": true,
  "enabled-42": true,
  "enabled-43": true,
  "enabled-44": true,
  "enabled-45": false,
  "abc-41": "some description 1",
  "abc-42": "some description 12",
  "abc-43": "some description 123",
  "abc-44": "some description 1234",
  "abc-45": null,
  "def-41": "some description 2",
  "def-42": "some description 23",
  "def-43": "some description 234",
  "def-44": "some description 2345",
  "def-45": null,
  "type-41": "def",
  "type-42": "abc",
  "type-43": "def",
  "type-44": "abc",
  "type-45": null,
  "weight-41": "25",
  "weight-42": "25",
  "weight-43": "25",
  "weight-44": "25",
  "weight-45": null
}

let arr = [
  {
    "id": 41,
    "abc": "some description 1",
    "def": "some description 2",
    "type": "def",
    "Criteria": {
      "id": 5,
      "question": "follow-up",
      "definition": "definition content",
      "status": true
    },
    "weight": 25,
    "enabled": true
  },
  {
    "id": 42,
    "abc": "some description 12",
    "def": "some description 23",
    "type": "abc",
    "Criteria": {
      "id": 1,
      "question": "coverage",
      "definition": "definition content",
      "status": true
    },
    "weight": 25,
    "enabled": true
  },
  {
    "id": 43,
    "abc": "some description 123",
    "def": "some description 234",
    "type": "def",
    "Criteria": {
      "id": 4,
      "question": "Price",
      "definition": "definition content",
      "status": true
    },
    "weight": 25,
    "enabled": true
  },
  {
    "id": 44,
    "abc": "some description 1234",
    "def": "some description 2345",
    "type": "abc",
    "Criteria": {
      "id": 3,
      "question": "Exchange",
      "definition": "definition content",
      "status": true
    },
    "weight": 25,
    "enabled": true
  },
  {
    "id": 45,
    "Criteria": {
      "id": 2,
      "definition": "definition conent",
      "question": "Random",
      "status": true
    },
    "type": null,
    "abc": null,
    "def": null,
    "weight": 0,
    "enabled": false
  }
];

let result = arr.reduce(function(obj, item) {
    obj[item] = item.value;
    return obj;
}, {})

console.log(result);

I have tried using reduce function, but cannot able to get the right way to convert to a single object with the above format based on dynamic key (joining id with hypen).

Can someone help me with this?

What about the Criteria object? What should happen? Should it be discarded? — Jack Bashford
– Jack Bashford, Commented Apr 30, 2019 at 4:40
Yes Criteria object can be discarded and want to get the single object as above — UI_Dev
– UI_Dev, Commented Apr 30, 2019 at 4:44

Jack Bashford · Accepted Answer · 2019-04-30 05:00:25Z

You can use reduce with Object.keys, and place all keys you wish to exclude in an array and check against that:

let arr = [{"id":41,"abc":"some description 1","def":"some description 2","type":"def","Criteria":{"id":5,"question":"follow-up","definition":"definition content","status":true},"weight":25,"enabled":true},{"id":42,"abc":"some description 12","def":"some description 23","type":"abc","Criteria":{"id":1,"question":"coverage","definition":"definition content","status":true},"weight":25,"enabled":true},{"id":43,"abc":"some description 123","def":"some description 234","type":"def","Criteria":{"id":4,"question":"Price","definition":"definition content","status":true},"weight":25,"enabled":true},{"id":44,"abc":"some description 1234","def":"some description 2345","type":"abc","Criteria":{"id":3,"question":"Exchange","definition":"definition content","status":true},"weight":25,"enabled":true},{"id":45,"Criteria":{"id":2,"definition":"definition conent","question":"Random","status":true},"type":null,"abc":null,"def":null,"weight":0,"enabled":false}];

let exclude = ["id", "Criteria"];

let result = arr.reduce((acc, curr) => {
  let id = curr.id;
  Object.entries(curr).forEach(([k, v]) => {
    if (!exclude.includes(k)) acc[`${k}-${id}`] = v;
  });
  return acc;
}, {});

console.log(result);

brk · Accepted Answer · 2019-04-30 04:51:13Z

4

You code is almost there. But object keys order is not guaranteed. Inside the reduce callback function add the keys in the accumulator and corresponding value.

Use template literals & square notation while creating the object keys

let arr = [{
    "id": 41,
    "abc": "some description 1",
    "def": "some description 2",
    "type": "def",
    "Criteria": {
      "id": 5,
      "question": "follow-up",
      "definition": "definition content",
      "status": true
    },
    "weight": 25,
    "enabled": true
  },
  {
    "id": 42,
    "abc": "some description 12",
    "def": "some description 23",
    "type": "abc",
    "Criteria": {
      "id": 1,
      "question": "coverage",
      "definition": "definition content",
      "status": true
    },
    "weight": 25,
    "enabled": true
  },
  {
    "id": 43,
    "abc": "some description 123",
    "def": "some description 234",
    "type": "def",
    "Criteria": {
      "id": 4,
      "question": "Price",
      "definition": "definition content",
      "status": true
    },
    "weight": 25,
    "enabled": true
  },
  {
    "id": 44,
    "abc": "some description 1234",
    "def": "some description 2345",
    "type": "abc",
    "Criteria": {
      "id": 3,
      "question": "Exchange",
      "definition": "definition content",
      "status": true
    },
    "weight": 25,
    "enabled": true
  },
  {
    "id": 45,
    "Criteria": {
      "id": 2,
      "definition": "definition conent",
      "question": "Random",
      "status": true
    },
    "type": null,
    "abc": null,
    "def": null,
    "weight": 0,
    "enabled": false
  }
];

let result = arr.reduce(function(obj, item) {
  obj[`enabled-${item.id}`] = item.enabled;
  obj[`abc-${item.id}`] = item.abc;
  obj[`def-${item.id}`] = item.def;
  obj[`type-${item.id}`] = item.type;
  obj[`weight-${item.id}`] = item.weight;
  return obj;
}, {});
console.log(result)

answered Apr 30, 2019 at 4:51

brk

50.3k10 gold badges59 silver badges85 bronze badges

3 Comments

UI_Dev Over a year ago

Thanks, is there any possibility with the object key order?

brk Over a year ago

@UI_Dev hopefully this link stackoverflow.com/questions/5525795/… will help you

Pierre Arlaud Over a year ago

@UI_Dev someone did

Shidersz · Accepted Answer · 2019-04-30 05:04:10Z

Assuming you want to exclude all the properties whose value is an object maybe you can go with this generic idea that uses Object.entries() to traverse the inner objects and some destructuring features.

let arr=[{"id":41,"abc":"some description 1","def":"some description 2","type":"def","Criteria":{"id":5,"question":"follow-up","definition":"definition content","status":true},"weight":25,"enabled":true},{"id":42,"abc":"some description 12","def":"some description 23","type":"abc","Criteria":{"id":1,"question":"coverage","definition":"definition content","status":true},"weight":25,"enabled":true},{"id":43,"abc":"some description 123","def":"some description 234","type":"def","Criteria":{"id":4,"question":"Price","definition":"definition content","status":true},"weight":25,"enabled":true},{"id":44,"abc":"some description 1234","def":"some description 2345","type":"abc","Criteria":{"id":3,"question":"Exchange","definition":"definition content","status":true},"weight":25,"enabled":true},{"id":45,"Criteria":{"id":2,"definition":"definition conent","question":"Random","status":true},"type":null,"abc":null,"def":null,"weight":0,"enabled":false}];

let result = arr.reduce((obj, {id, ...rest}) =>
{
    Object.entries(rest).forEach(([k, v]) =>
    {
        if (Object(v) !== v) obj[`${k}-${id}`] = v;
    });

    return obj;
}, {});

console.log(result);

.as-console {background-color:black !important; color:lime;}
.as-console-wrapper {max-height:100% !important; top:0;}

tagyoureit · Accepted Answer · 2019-04-30 05:06:33Z

1

Oh, man... I just got beat. Here's my solution.

let arr= [] // hold the final object array
let keys = [] // temp item to hold the value of each key

    // iterate over each key
    Object.keys(input).forEach((key) => {  
    let pair = key.split('-') // split the key into the real key and the index

    // if the index isn't in the array, push it there (this keeps the same order)
    if (keys.indexOf(pair[1])===-1) { 
        keys.push(pair[1])
    }

    // use object.assign to add the keys to the existing object in the right place in the array. 
    arr[keys.indexOf(pair[1])] = Object.assign({}, arr[keys.indexOf(pair[1])], {[pair[0]]: input[key]}, { id: pair[1] }) 

})

answered Apr 30, 2019 at 5:06

tagyoureit

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Comments

Mohammed Ashfaq · Accepted Answer · 2019-04-30 09:05:04Z

function getFilteredData(arr) {
  const result = {};
  arr.forEach(item => {
    const { id, Criteria, ...rest } = item;
    Object.entries(rest).map(([key, value]) => {
      result[`${key}-${id}`] = value;
    });
  });
  return result;
}

let arr = [
  {
    id: 41,
    abc: 'some description 1',
    def: 'some description 2',
    type: 'def',
    Criteria: {
      id: 5,
      question: 'follow-up',
      definition: 'definition content',
      status: true
    },
    weight: 25,
    enabled: true
  },
  {
    id: 42,
    abc: 'some description 12',
    def: 'some description 23',
    type: 'abc',
    Criteria: {
      id: 1,
      question: 'coverage',
      definition: 'definition content',
      status: true
    },
    weight: 25,
    enabled: true
  },
  {
    id: 43,
    abc: 'some description 123',
    def: 'some description 234',
    type: 'def',
    Criteria: {
      id: 4,
      question: 'Price',
      definition: 'definition content',
      status: true
    },
    weight: 25,
    enabled: true
  },
  {
    id: 44,
    abc: 'some description 1234',
    def: 'some description 2345',
    type: 'abc',
    Criteria: {
      id: 3,
      question: 'Exchange',
      definition: 'definition content',
      status: true
    },
    weight: 25,
    enabled: true
  },
  {
    id: 45,
    Criteria: {
      id: 2,
      definition: 'definition conent',
      question: 'Random',
      status: true
    },
    type: null,
    abc: null,
    def: null,
    weight: 0,
    enabled: false
  }
];

console.log(getFilteredData(arr));

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