Loop through nested json array to create new array

Question

I am working on a lambda function that GETs data from one API and POSTs it to another. The data is a list of contacts with properties, e.g. first name, last name, email, etc.

The JSON output contains too many properties that I don't need. See below code example (actual code contains many more properties and nested arrays/objects).

{
  "contacts": [
      {
          "addedAt": 1532803458796,
          "vid": 101
      }
   ],
  "merge-audits": [],
  "properties": {
       "first-name": {
          "value":"hello"
        },
        "last-name": {
          "value":"there"
        },
        "email": {
          "value":"[email protected]"
        }
... 
...
}

How can I loop through each JSON object to create a new, simpler JSON array like the following:

[
  {
    "email": "[email protected]",
    "first_name": "",
    "last_name": "User"
  },
  {
    "email": "[email protected]",
    "first_name": "Example",
    "last_name": "User"
  }
]

Thanks in advance for your help.

JSON is text. When you say "raw JSON" you seem to be really stressing it is JSON... but is it? Or are we starting out with a JavaScript object? — trincot
– trincot, Commented Apr 2, 2019 at 20:52
does your json have multiple keys called properties or something? — Chris Li
– Chris Li, Commented Apr 2, 2019 at 20:54

Kamil Kiełczewski · Accepted Answer · 2019-04-02 21:12:37Z

1

try

json.map( x => ({
  email:      x.properties.email.value,
  first_name: x.properties['first-name'].value,
  last_name:  x.properties['last-name'].value,
}));

let json = [
{
  "contacts": [{
    "addedAt": 1532803458796,
    "vid": 101
  }],
  "merge-audits": [],
  "properties": {
    "first-name": {
      "value": "hello"
    },
    "last-name": {
      "value": "there",
    },
    "email": {
      "value": "[email protected]"
    }
  }
},
{
  "contacts": [{
    "addedAt": 1532803458796,
    "vid": 101
  }],
  "merge-audits": [],
  "properties": {
    "first-name": {
      "value": "Tom"
    },
    "last-name": {
      "value": "Smith",
    },
    "email": {
      "value": "[email protected]"
    }
  }
}
]

let r = json.map(x => ({
  email:      x.properties.email.value,
  first_name: x.properties['first-name'].value,
  last_name:  x.properties['last-name'].value,
}));

console.log(r);

answered Apr 2, 2019 at 21:12

Kamil Kiełczewski

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1 Comment

systemajik Over a year ago

Tested, worked perfectly and very efficient, thank you!

Nina Scholz · Accepted Answer · 2019-04-02 21:00:48Z

1

You could use a destructuring assignment for the object and short hand properties for the mapping.

var data = [{ contacts: [{ addedAt: 1532803458796, vid: 101 }], "merge-audits": [], properties: { "first-name": { value: "hello" }, "last-name": { value: "there" }, email: { value: "[email protected]" } } }],
    result = data.map(({ properties: {
        'first-name': { value: first_name },
        'last-name': { value: last_name },
         email: { value: email }
    } }) => ({ first_name, last_name, email }));

console.log(result);

edited Apr 2, 2019 at 21:00

answered Apr 2, 2019 at 20:55

Nina Scholz

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2 Comments

systemajik Over a year ago

Your solution also produces the same results. Thank you for the additional information. Would this also work for multiple objects in the data variable?

Nina Scholz Over a year ago

it does, because data is an array and each same organized object gets converted.

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