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!

Answer 1

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> 

Answer 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); 

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Answer 3

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) 

Answer 4

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) 

Answer 5

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/lodash@4.17.5/lodash.min.js"></script> 

Answer 6

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)