From nested array to array of object

Question

I have a nested array like this

array = [[1, 698],[32, 798],[69, 830],[95, 500]]

I want to have a function that return the result in this format

[
    {
        id: 1,
        score: 698
    },
    {
        id: 32,
        score: 798
    },
    {
        id: 69,
        score:830
    },
  ..... the rest of the array
]

I did use a for loop but with no success, and I have no idea on how to aproach the situation.

for(var i = 0; i <= array.lenght ; i++){
    var obj={}
    var res = []
    res.push(array[i])
}

Just to clarify why this is not working: you re-create res in each iteration from scratch, so you don't push the mapped data to the same array each time — Nico Haase
– Nico Haase, Commented Mar 27, 2018 at 14:53

Mamun · Accepted Answer · 2018-03-27 14:48:22Z

10

You can take the advantage of the power of the ES6 syntax:

var array = [
          [1, 698],
          [32, 798],
          [69, 830],
          [95, 500],
        ];
var res = array.map(([id, score]) => ({id, score}));
console.log(res);

edited Mar 27, 2018 at 14:48

Mamun

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answered Mar 27, 2018 at 14:36

Abslen Char

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Comments

Yosvel Quintero · Accepted Answer · 2018-03-27 14:40:00Z

6

You can use Array.prototype.map() with destructuring assignment:

const array = [[1, 698],[32, 798],[69, 830],[95, 500]];
const result = array.map(([id, score]) => ({id, score}));

console.log(result);

answered Mar 27, 2018 at 14:40

Yosvel Quintero

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Comments

Faly · Accepted Answer · 2018-03-27 14:37:09Z

4

Use array.prototype.map, destructuring and shorthand object litteral:

var array = [[1, 698],[32, 798],[69, 830],[95, 500]];
var result = array.map(([id, score]) => ({id, score}));
console.log(result);

answered Mar 27, 2018 at 14:37

Faly

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Comments

MyTwoCents · Accepted Answer · 2018-03-27 14:38:46Z

3

var sampleArray = [[1, 698],[32, 798],[69, 830],[95, 500]];

var finalJson = sampleArray.map(([id, score]) => ({id, score}));


// Final Result
console.log(finalJson);

answered Mar 27, 2018 at 14:38

MyTwoCents

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Comments

Jason · Accepted Answer · 2018-03-27 14:47:20Z

2

first you need a function that takes a 2 element array and returns an object

const objBuilder = arr => return { id: arr[0], score: arr[1] }

you will want to add error handling, but thats the basic idea.

Next you want to iterate over the array of arrays transforming each value (2 element array) into an object. Thats called mapping over values, and js supports it natively

const arrayOfObjects =  array.map(objBuilder)

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

edited Mar 27, 2018 at 14:47

answered Mar 27, 2018 at 14:41

Jason

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Comments

Scott Sauyet · Accepted Answer · 2018-03-27 15:20:30Z

2

The answers from a number of people suggesting .map(([id, score]) => ({id, score})) are great. But if you have to do things like this often, you might want to write a reusable function to make this more declarative. For that, something like this might work:

const zipObject = names => values => names.reduce(
  (obj, name, idx) => (obj[name] = values[idx], obj), {}
)

const array = [[1, 698], [32, 798], [69, 830], [95, 500]]
console.log(array.map(zipObject(['id', 'score'])))

Note that you could also extend this to

zipAllObjects = names => listsOfValues => listsOfValues.map(zipObject(names))

and just call

zipAllObjects(['id', 'score'])(array)

edited Mar 27, 2018 at 15:20

answered Mar 27, 2018 at 14:52

Scott Sauyet

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2 Comments

Abslen Char Over a year ago

i like your approach , but i am not sur if the the OP will be able to understand it

Scott Sauyet Over a year ago

@AbdeslemCharif: Thanks. You're quite possibly right, but I like pushing even slightly more functional approaches when possible.

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