JS convert arrays into object then replace object key with property value

Question

I need to convert an array into objects and then need to move one of object property value as a object property key name:

[
  {
    "description": "red",
    "type": "fruit",
    "item": "apple"
  },
  {
    "description": "yellow",
    "type":"fruit",
    "item": "banana"
  }
]

into

{
  "apple": {
    "description": "red",
    "type": "fruit"
  },
  "banana": {
    "description": "yellow",
    "type": "fruit"
  }
}

using Object.assign({}, ...arr) populates object's names into index, i need to change that index, thanks!

Just iterate over that array and place entries into a new object. — Andrew
– Andrew, Commented Apr 11, 2018 at 23:01

synthet1c · Accepted Answer · 2018-04-11 23:02:59Z

3

You can use Array#reduce to fold your array into an object. using destructuring you can pull out the values from the object and create a new object in your desired format for the output.

const data = [
  {
    "description": "red",
    "type": "fruit",
    "item": "apple"
  },
  {
    "description": "yellow",
    "type":"fruit",
    "item": "banana"
  }
]

console.log(
  data.reduce((accumulator, { item, description, type }) => ({
    ...accumulator,
    [item]: { description, type }
  }), {})
)

<script src="https://codepen.io/synthet1c/pen/KyQQmL.js"></script>

answered Apr 11, 2018 at 23:02

synthet1c

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4 Comments

Ele Over a year ago

Love that plugin!! (:

synthet1c Over a year ago

@Ele cheers, I wasn't happy with the stackoverflow console so made a simple one to help with presenting the results.

Ele Over a year ago

Some upvoted answers cuz you've shared with us that plugin!!

synthet1c Over a year ago

Cheers guys, feel free to use / fork it. it has an assertion library based on jasmine's api built in if you need it, there is examples at the bottom of the codepen, just remove the .js to see the pen.

Ele · Accepted Answer · 2018-04-11 23:19:41Z

2

You can use the function Array.prototype.reduce to build the desired output.

var array = [  {    "description": "red",    "type": "fruit",    "item": "apple"  },  {    "description": "yellow",    "type":"fruit",    "item": "banana"  }],
    result = array.reduce((a, {description, type, item}) => (Object.assign(a, {[item]: {description, type}})), {});

console.log(result);

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

<script src="https://codepen.io/synthet1c/pen/KyQQmL.js"></script>

Unrelated: Nice console plugin from @synthet1c

edited Apr 11, 2018 at 23:19

answered Apr 11, 2018 at 23:02

Ele

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Comments

mpen · Accepted Answer · 2018-04-11 23:03:56Z

0

Can be done with a single call to reduce.

const data = [{
    "description": "red",
    "type": "fruit",
    "item": "apple"
  },
  {
    "description": "yellow",
    "type": "fruit",
    "item": "banana"
  }
]

const regrouped = data.reduce((acc, {
  description,
  type,
  item
}) => {
  acc[item] = {
    description,
    type
  }
  return acc
}, {});

console.log(regrouped)

answered Apr 11, 2018 at 23:03

mpen

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Comments

Spencer Wieczorek · Accepted Answer · 2018-04-11 23:05:44Z

0

One way is using a forEach on the array and build an object based on the properties:

var arr = [{"description": "red", "type": "fruit", "item": "apple"},{"description":"yellow","type":"fruit","item": "banana"}]

obj = {};
arr.forEach((o) => {
    obj[o.item] = o;
    delete o.item;
});

console.log(obj)

answered Apr 11, 2018 at 23:05

Spencer Wieczorek

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Comments

CRice · Accepted Answer · 2018-04-11 23:08:39Z

0

Other answers have covered the vanilla JS solution quite well, but if you can use lodash, you can do this by combining the methods keyBy, mapValues, and omit to produce a nice one-liner:

const myArray = [{
  "description": "red",
  "type": "fruit",
  "item": "apple"
}, {
  "description": "yellow",
  "type": "fruit",
  "item": "banana"
}];

const result = _.mapValues(_.keyBy(myArray, o => o.item), o => _.omit(o, "item"));
console.log(result);

<script src="https://cdn.jsdelivr.net/npm/[email protected]/lodash.min.js"></script>

answered Apr 11, 2018 at 23:08

CRice

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Comments

sumit · Accepted Answer · 2018-04-11 23:10:09Z

0

You can use reduce

let arr=[
  {
    "description": "red",
    "type": "fruit",
    "item": "apple"
  },
  {
    "description": "yellow",
    "type":"fruit",
    "item": "banana"
  }
]
const convert_to_object = (myarray) =>
   myarray.reduce((o, i) => {
     o[i.item] = {description:i.description,type:i.type}
     return o
   }, {})
const peopleObject = convert_to_object(arr)
console.log(peopleObject)

answered Apr 11, 2018 at 23:10

sumit

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