Create a new JSON array from nested key/values of existing JSON array

Question

I have an array of Objects which will always be structured like so:

var initialJSON = [  
  {  
     "id":"01",
     "name":"Jane",
     "project":{  
        "title":"Alpha",
        "description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit",
        "city":"New York"
     },
     "dateCreated":"2018-04-28 04:11:16 UTC"
   },
   {  
     "id":"02",
     "name":"Sarah",
     "project":{  
       "title":"Beta",
       "description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit",
       "city":"London"
     },
      "dateCreated":"2018-04-28 04:11:29 UTC"
    },
    {  
      "id":"03",
      "name":"Mia",
      "project":{  
         "title":"Gamma",
         "description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit",
         "city":"Paris"
      },
      "dateCreated":"2018-04-28 04:11:29 UTC"
   }
];

My goal is to create a new array of Objects containing just the key/values of each item's projects. Essentially removing all of the other data (including the parent key 'project') from each item.

The end result would look like so:

var formattedJSON = [
  {
    "title":"Alpha",
    "description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit",
    "city":"New York"
  },
  {
    "title":"Beta",
    "description": "Lorem ipsum dolor sit amet, consectetur adipiscing elit",
    "city":"London"
  },
  {
    "title":"Gamma",
    "description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit",
    "Paris"
  }
]

I am having difficulty finding a way to loop through the data and achieve the correct result. I am aware there are similar questions already posted but non seem to create a new array out of the nested key/values of an inner key.

Luca Kiebel · Accepted Answer · 2018-08-12 23:42:05Z

2

You can use Array#map() for this, by assigning each element of the array to it's project property:

let initialJSON=[{"id":"01","name":"Jane","project":{"title":"Alpha","description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit","city":"New York"},"dateCreated":"2018-04-28 04:11:16 UTC"},{"id":"02","name":"Sarah","project":{"title":"Beta","description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit","city":"London"},"dateCreated":"2018-04-28 04:11:29 UTC"},{"id":"03","name":"Mia","project":{"title":"Gamma","description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit","city":"Paris"},"dateCreated":"2018-04-28 04:11:29 UTC"}];

let result = initialJSON.map(element => element.project);

console.log(result)

edited Aug 12, 2018 at 23:42

answered Aug 12, 2018 at 23:33

Luca Kiebel

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Comments

Dacre Denny · Accepted Answer · 2018-08-12 23:35:20Z

0

You could use the map function on the initialJSON array to achieve this, in the following way:

var formattedJSON = initialJSON.map(item => {

  // For each item in the "initialJSON", map the fields to each item 
  // in the "formattedJSON" array
  return {
    title : item.project.title,
    description : item.project.description,
    city : item.project.city
  }

})

edited Aug 12, 2018 at 23:35

answered Aug 12, 2018 at 23:33

Dacre Denny

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1 Comment

Luca Kiebel Over a year ago

This is complicating things more than it should, item.project is already an Object, that you can return

Slai · Accepted Answer · 2018-08-12 23:51:36Z

0

The JSON.parse reviver parameter can be used to change or exlude values:

var j = '[{"id":"01","name":"Jane","project":{"title":"Alpha","description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit","city":"New York"},"dateCreated":"2018-04-28 04:11:16 UTC"},{"id":"02","name":"Sarah","project":{"title":"Beta","description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit","city":"London"},"dateCreated":"2018-04-28 04:11:29 UTC"},{"id":"03","name":"Mia","project":{"title":"Gamma","description":"Lorem ipsum dolor sit amet, consectetur adipiscing elit","city":"Paris"},"dateCreated":"2018-04-28 04:11:29 UTC"}]'

let result = JSON.parse(j, (k, v) => v.project || v);

console.log( result )

answered Aug 12, 2018 at 23:51

Slai

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