JavaScript Array attribute change

Question

I have an array like this.

let arr = [
  {
    "ABBRIVATION":"ISB",
    "name":"ISLAMABAD",
  },
  {
    "ABBRIVATION":"RAW",
    "name":"PINDI",
  },
  {
    "ABBRIVATION":"SWB",
    "name":"SWABI",
  },
  {
    "ABBRIVATION":"AQ",
    "name":"AQEEL",
  },
]

I want to change it to like this let me explain it a little. I want to assign the abbreviation directly to the name and the iterate through that array

let outout = [
  {
    "ISB":"ISLAMABAD"
  },
  {
    "RAW":"ISLAMABAD"
  },
  {
    "SWB":"SWABI"
  },
  {
    "AQ":"AQEEL"
  },
]

that is what I tried

let k = arr.map((item) => {
  return item.ABB = item.name
})
console.log(k)

and here is the output

[ 'ISLAMABAD', 'PINDI', 'SWABI', 'AQEEL' ]

Bravo · Accepted Answer · 2021-08-12 06:33:31Z

4

Here you go, use array map, simples

let arr = [
  {
    "ABBRIVATION":"ISB",
    "name":"ISLAMABAD",
  },
  {
    "ABBRIVATION":"RAW",
    "name":"PINDI",
  },
  {
    "ABBRIVATION":"SWB",
    "name":"SWABI",
  },
  {
    "ABBRIVATION":"AQ",
    "name":"AQEEL",
  },
]

let outout = arr.map(({ABBRIVATION, name}) => ({[ABBRIVATION]: name}));
console.log(outout);

answered Aug 12, 2021 at 6:33

Bravo

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Comments

Behemoth · Accepted Answer · 2021-08-12 06:33:58Z

3

Nothing more than a simple Array.prototype.map() needed.

let arr = [
  {
    ABBRIVATION: "ISB",
    name: "ISLAMABAD",
  },
  {
    ABBRIVATION: "RAW",
    name: "PINDI",
  },
  {
    ABBRIVATION: "SWB",
    name: "SWABI",
  },
  {
    ABBRIVATION: "AQ",
    name: "AQEEL",
  },
];

const result = arr.map(e => ({ [e.ABBRIVATION]: e.name }));
console.log(result);

answered Aug 12, 2021 at 6:33

Behemoth

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Comments

Andy · Accepted Answer · 2021-08-12 06:45:58Z

3

map over the array of objects (map returns a new array) and assign the name to a new key defined by the abbreviation.

You code works the way it does because item.ABB is undefined, but you're also assigning item.name to it which does get returned, so you just get an array of names returned.

const arr=[{ABBRIVATION:"ISB",name:"ISLAMABAD"},{ABBRIVATION:"RAW",name:"PINDI"},{ABBRIVATION:"SWB",name:"SWABI"},{ABBRIVATION:"AQ",name:"AQEEL"}];

const out = arr.map(obj => {
  return { [obj.ABBRIVATION]: obj.name };
});

console.log(out);

edited Aug 12, 2021 at 6:45

answered Aug 12, 2021 at 6:35

Andy

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Comments

Ian · Accepted Answer · 2021-08-12 07:57:06Z

Hi I have seen people answer, but most of them use the map function, I provide some other solutions, hoping to expand the thinking

Use forEach function

const datas = [
  {
    "ABBRIVATION":"ISB",
    "name":"ISLAMABAD",
  },
  {
    "ABBRIVATION":"RAW",
    "name":"PINDI",
  },
  {
    "ABBRIVATION":"SWB",
    "name":"SWABI",
  },
  {
    "ABBRIVATION":"AQ",
    "name":"AQEEL",
  }
];

datas.forEach((obj, i, arr) => {
  const{'ABBRIVATION':k, 'name':v} = obj;
  arr[i] = {[k]:v};
});

console.log(datas);

Use flatMap function

const datas = [
  {
    "ABBRIVATION":"ISB",
    "name":"ISLAMABAD",
  },
  {
    "ABBRIVATION":"RAW",
    "name":"PINDI",
  },
  {
    "ABBRIVATION":"SWB",
    "name":"SWABI",
  },
  {
    "ABBRIVATION":"AQ",
    "name":"AQEEL",
  }
];

const result = datas.flatMap(obj => {
  const {'ABBRIVATION':k, 'name':v} = obj;
  return {[k]:v};
});

console.log(result);

Ernesto · Accepted Answer · 2021-08-12 06:58:55Z

-2

this is how you suppose to do it.

arr.reduce((d, c)=>([...d, {[c.ABBRIVATION]: c.name}]),[])

let arr = [
  {
    "ABBRIVATION":"ISB",
    "name":"ISLAMABAD",
  },
  {
    "ABBRIVATION":"RAW",
    "name":"PINDI",
  },
  {
    "ABBRIVATION":"SWB",
    "name":"SWABI",
  },
  {
    "ABBRIVATION":"AQ",
    "name":"AQEEL",
  },
]

console.log(arr.reduce((data, current)=>([...data, {[current.ABBRIVATION]: current.name}]),[]))

answered Aug 12, 2021 at 6:58

Ernesto

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3 Comments

Bravo Over a year ago

why are you suppose to do it like this? why must you abuse reduce to work just like map? why? please explain why this is at all better than using map?

Behemoth Over a year ago

How is reduce the better option here? You basically mapped the array without using map??

AKX Over a year ago

I agree that this is useless use of reduce. This code is about 26% slower than the .map solution according to JSBench.

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