CODEWITHSUNDEEP
javascript
lecham
lecham

Reputation: 2464

Remove nested array from an object

What is the best way to convert 

const mockResults = [
    [{ user: { firstName: '1', lastName: '1' }, status: 'WRONG' }],
    [{ user: { firstName: '2',lastName: '2' }, status: 'WRONG' }],
    [{ user: { firstName: '3',lastName: '3' }, status: 'CORRECT' }]
];

to

const mockResults = [
    { user: { firstName: '1', lastName: '1' }, status: 'WRONG' },
    { user: { firstName: '2',lastName: '2' }, status: 'WRONG' },
    { user: { firstName: '3',lastName: '3' }, status: 'CORRECT' }
];

The whole task is to transform mockResults to requiredFormat, that's why I need to remove nested arrays:

const requiredFormat = [
  {
    status: 'WRONG',
    data: [{ user: {firstName: '1', lastName: '1'}}, { user: {firstName: '2', lastName: '2'}}],
  },
  {
    status: 'CORRECT',
    data: [{ user: {firstName: '3', lastName: '3'}}],
  },
];

Here's what I tried so far: https://jsfiddle.net/9uLje3sg/

Thanks!

Upvotes: 1

Views: 93

Answers (4)

Mohammad Faisal
Mohammad Faisal

Reputation: 2402

const mockResults = [
    [{ user: { firstName: '1', lastName: '1' }, status: 'WRONG' }],
    [{ user: { firstName: '2',lastName: '2' }, status: 'WRONG' }],
    [{ user: { firstName: '3',lastName: '3' }, status: 'CORRECT' }]
];
const requiredFormat = [
  {status: 'WRONG', data: []},
  {status: 'CORRECT', data: []},
];

for(let [{user,status}] of mockResults) {  
  requiredFormat[ status==="WRONG" ? 0 : 1].data.push({user});
}
console.log(requiredFormat);

Upvotes: 0

jmtalarn
jmtalarn

Reputation: 1723

You can use flat method from Array javascript object. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat

If you want to change the source of data and change the shape of it, using map and reduce methods can help you.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce

In your precise example reduce would fit as you are creating a new object grouping per status property.

const mockResults = [
    [{ user: { firstName: '1', lastName: '1' }, status: 'WRONG' }],
    [{ user: { firstName: '2',lastName: '2' }, status: 'WRONG' }],
    [{ user: { firstName: '3',lastName: '3' }, status: 'CORRECT' }]
];
const flattedAndReduced = mockResults.flat().reduce( (acc, curr)=>{
  const statusIndex = { 'WRONG' : 0, 'CORRECT': 1 };
  acc[statusIndex[curr.status]].data.push({ user: curr.user} );
  return acc;
}, [
    {
      status: 'WRONG',
      data: [],
    },
    {
      status: 'CORRECT',
      data: [],
    }
  ]
  );
console.log(flattedAndReduced);

Upvotes: 4

Ele
Ele

Reputation: 33726

Use the function map as follow which returns an array with the desired objects.

let result = mockResults.map(([user]) => user);

That approach is assuming there is only one index per array from the original array.

According to the approach for requiredFormat

You can use the function reduce for grouping and the function Object.values for getting the desired output.

const mockResults = [
    [{ user: { firstName: '1', lastName: '1' }, status: 'WRONG' }],
    [{ user: { firstName: '2',lastName: '2' }, status: 'WRONG' }],
    [{ user: { firstName: '3',lastName: '3' }, status: 'CORRECT' }]
];

let requiredFormat = Object.values(mockResults.reduce((a, [{user, status}]) => {
  (a[status] || (a[status] = {data: [], status})).data.push(user);
  return a;
}, Object.create(null)));

console.log(requiredFormat);
.as-console-wrapper { max-height: 100% !important; top: 0; }

Upvotes: 2

Mamun
Mamun

Reputation: 68933

Simply use Array.prototype.map() to return the object from first index.

Please Note: variable declared with const can not be modified, use *let instead.

let mockResults = [
    [{ user: { firstName: '1', lastName: '1' }, status: 'WRONG' }],
    [{ user: { firstName: '2',lastName: '2' }, status: 'WRONG' }],
    [{ user: { firstName: '3',lastName: '3' }, status: 'CORRECT' }]
];

mockResults = mockResults.map(i => i[0]);
console.log(mockResults);

Upvotes: 1

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