Build Json from an array of objects

user_3523169 0
Viewed 112

I'm trying to use typescript to build a json object from an array of objects like this one:[ 

[
  { attribute: 'a', modifier: 121 },
  { attribute: 'b', modifier: 67 },
  { attribute: 'c', modifier: 121 },
  { attribute: 'd', modifier: 67 } 
]

I would like to get something like:

{
  a:  121,
  b:  67,
  c:  121,
  d:  67  
}

But I just can't get my head around the high order functions to make it work.

typescript functional-programming json javascript
3 Answers

You could use reduce method which accepts as parameter a callback function.

Read more about reduce method here.

let array=[
  { attribute: 'a', modifier: 121 },
  { attribute: 'b', modifier: 67 },
  { attribute: 'c', modifier: 121 },
  { attribute: 'd', modifier: 67 } 
];
let obj=array.reduce(function(obj,item){
  obj[item.attribute] = item.modifier;
  return obj;
},{});
console.log(obj);

user_65831400

You could use Object.assign in combination with Array#map.

var array = [{ attribute: 'a', modifier: 121 }, { attribute: 'b', modifier: 67 }, { attribute: 'c', modifier: 121 }, { attribute: 'd', modifier: 67 }],
    result = Object.assign(...array.map(o => ({ [o.attribute]: o.modifier })));

console.log(result);

With destructuring assignment

var array = [{ attribute: 'a', modifier: 121 }, { attribute: 'b', modifier: 67 }, { attribute: 'c', modifier: 121 }, { attribute: 'd', modifier: 67 }],
    result = Object.assign(...array.map(({ attribute, modifier }) => ({ [attribute]: modifier })));

console.log(result);

user_14476750

try this.

var arr = [
  { attribute: 'a', modifier: 121 },
  { attribute: 'b', modifier: 67 },
  { attribute: 'c', modifier: 121 },
  { attribute: 'd', modifier: 67 } 
]
var map = {};
arr.forEach( function(item){ map[ item.attribute ] = item.modifier });
console.log( JSON.stringify( map, 0, 4 ) )

user_19840390
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