使用 reducer 将嵌套的对象数组转换为键值对的 object

Question

I have an observable output like below. I want to convert this data to desired format(proivded below). I am partially successful forming key value pairs but couldn't figure out how to send only one field(that is for which selected is true ) from the cars array to final output.

***Observable Output****

[{
  "name":"John",
  "age":30,
  "cars": [
      { "selected":true,  "name":"Ford", "models": "Mustang"},
      { "selected":false, "name":"BMW", "models": "320" },
      { "selected":true, "name":"Fiat", "models":"500" }
  ]
 },
 {
  "name":"alex",
  "age":40,
  "cars": [
      { "selected":true,  "name":"tesla", "models": "x"},
      { "selected":false, "name":"merc", "models": "300" },
      { "selected":true, "name":"honda", "models":"accord" }
   ]
  }
]

****Desired Format*****

{John:[ford, fiat], Alex:[tesla,honda]} 

***Code used*****

const results = item.reduce((r,{name,cars}) => (r[name]=cars,r), {})

//This gives me complete cars object but i need only name from it(and that too for selected true ones).

Edit 1: Do not want to have empty record in the final object. For eg, if Alex does not have any Cars Selected True then i do not want Alex:[] in the final object.

Answer 1

this snippet will help

 const array = [{
  "name":"John",
  "age":30,
  "cars": [
      { "selected":true,  "name":"Ford", "models": "Mustang"},
      { "selected":false, "name":"BMW", "models": "320" },
      { "selected":true, "name":"Fiat", "models":"500" }
  ]
 },
 {
  "name":"alex",
  "age":40,
  "cars": [
      { "selected":true,  "name":"tesla", "models": "x"},
      { "selected":false, "name":"merc", "models": "300" },
      { "selected":true, "name":"honda", "models":"accord" }
   ]
  }
]


const newArray = array.reduce((acc, rec) => {
  const cars = rec.cars.filter(c => c.selected)

  return cars.length ? {...acc, [rec.name]: cars.map(c => c.name)} : acc
}, {})

console.log(newArray)

Answer 2

use forEach and build an object

Update: another solution using reduce

 data = [ { name: "John", age: 30, cars: [ { selected: true, name: "Ford", models: "Mustang" }, { selected: false, name: "BMW", models: "320" }, { selected: true, name: "Fiat", models: "500" }, ], }, { name: "alex", age: 40, cars: [ { selected: false, name: "tesla", models: "x" }, { selected: false, name: "merc", models: "300" }, { selected: false, name: "honda", models: "accord" }, ], }, ]; const output = data.reduce((acc, { name, cars }) => { const items = cars.filter(({selected}) => selected).map(({name}) => name); if (items.length > 0) { acc[name] = items; } return acc; }, {}); console.log(output);