CODEWITHSUNDEEP
javascript
DanielJ
DanielJ

Reputation: 769

Return Object from map() function not Array

Sorry if the title is misleading I'm not sure how to accurately describe what I am looking for.

I have an array result which I want to turn into multiple objects where each objects property is the field Name Test I need to keep my result.map method as I use it to merge result with data 

  result = [{
      "Name Test": "Yellow",
      Count: 124,

    },
    {
      "Name Test": "Black",
      Count: 124,
    },
    {
      "Name Test": "Blue",
      Count: 124,
    }
  ];

  data = [{
      "Name Test": "Yellow",
      pop: 1
    },
    {
      "Name Test": "Black",
      pop: 1
    },
    {
      "Name Test": "Blue",
      pop: 1
    }
  ];


result = result.map((obj1, index) => {
    const obj2 = data[index];
    return {
        [obj1["Name Test"].toUpperCase()]: {
            Count: obj1.Count,
            pop: obj2.pop,
        }
    };
});
console.log(JSON.stringify(result))

This code returns an array of objects which is not what I want as I need to be able to use result["YELLOW"] later in my code. I therefore need the result to be in this format, with no arrays.

{  
   "YELLOW":{  
      "Count":124,
      "pop":1
   },
   "BLACK":{  
      "Count":124,
      "pop":1
   },
   "BLUE":{  
      "Count":124,
      "pop":1
   }
}

I hope this makes sense and I feel I am very close to what I want and just am missing something small, but every way I have tried to make this work turns into a syntax error.

Upvotes: 9

Views: 22615

Answers (3)

Mark
Mark

Reputation: 92440

It's not available in MS browsers yet, (I think), but fromEntries() is pretty nice for this. You can pass it an iterable or key.value pairs, such as the results from map().

let result = [{"Name Test": "Yellow",Count: 124,pop: 1},{"Name Test": "Black",Count: 124,pop: 1},{"Name Test": "Blue",Count: 124,pop: 1}];
let data = [{"Name Test": "Yellow",pop: 1},{"Name Test": "Black",pop: 1},{"Name Test": "Blue",pop: 1}];

let o = Object.fromEntries(result.map(({'Name Test':n, ...o}) => ([n, o])))
let d = Object.fromEntries(result.map(({'Name Test':n, ...o}) => ([n, o])))
 
console.log(Object.assign(o, d))

Upvotes: 1

brk
brk

Reputation: 50291

map will create a new array. So you can use reduce and pass an empty object in the accumulator

let result = [{
    "Name Test": "Yellow",
    Count: 124,
    pop: 1
  },
  {
    "Name Test": "Black",
    Count: 124,
    pop: 1
  },
  {
    "Name Test": "Blue",
    Count: 124,
    pop: 1
  }
];

let newResult = result.reduce(function(acc, curr) {
  // acc is accumulator which is the required object.
  // this will create a nee key in accumulator and will set its value
  acc[curr['Name Test'].toUpperCase()] = {
    Count: curr.Count,
    pop: curr.pop
  }
 return acc;
}, {}) // {} is accumulator object. This will hold the required keys and values

console.log(newResult)

Upvotes: 5

Maheer Ali
Maheer Ali

Reputation: 36564

map() will always return an array.

  • You should use reduce() and set accumulator to empty object {}

  • Use the destructuring and spread syntax to isolate Name Test and other properties.

  • Set the property of accumulator whose key is "Name Test" property of each object and its value is rest of the object.

const arr = [{ "Name Test": "Yellow", Count: 124, pop: 1 }, { "Name Test": "Black", Count: 124, pop: 1 }, { "Name Test": "Blue", Count: 124, pop: 1 } ];

const res = arr.reduce((ac,{["Name Test"]:x,...rest}) => (ac[x] = rest,ac),{})

console.log(res)

Upvotes: 10

Related Questions