How do I create a new object from an existing object in Javascript?

Question

Working on JavaScript app and need help in creating a new object from response received from ajax call.

The output received is array of objects, sample format below:

{
  "items": [
    {
      "id": "02egnc0eo7qk53e9nh7igq6d48",
      "summary": "Learn to swim",
      "start": {
        "dateTime": "2017-03-04T19:00:00+05:30"
      }
    }        

]
}

However, my component expects JS Object in the following format:

{
id: "e1",
title: "Express",
start: "Jan 13, 2010",
description: "Jan 13, 2010"
}

Is following approach correct, please suggest better approach if any

var content = {
    "items": [{
        "id": "02egnc0eo7qk53e9nh7igq6d48",
        "summary": "Learn to code",
        "start": {
          "dateTime": "2017-03-04T19:00:00+05:30"
        }
      }
      }
    };
    var gcalEvents = {};
    var jsonObj = {
      "id": "e1",
      "title": "Oracle Application Express",
      "start": "Jan 13, 2010",
      "description": "Jan 13, 2010"
    };

    console.log(content.items.length);
    for (var index = 0; index < content.items.length; index++) {
      var obj = content.items;
      console.log(obj);

      jsonObj.id = obj[index]["id"];
      jsonObj.title = obj[index].summary;
      jsonObj.start = obj[index].start.dateTime;
      jsonObj.description = "";
      console.log(jsonObj);
      gcalEvents[index] = jsonObj;
    }
    console.log(gcalEvents);

Answer 1

You could take a more functional approach with the following:

var parsed = content.items.map(function (item) {
    return {
        id: item.id,
        title: item.summary,
        start: item.start.dateTime,
        description: item.start.dateTime
    }
})

This uses the map method that is attributed with arrays to loop over each item of the array and return a new array of parsed objects.

Take a look at this fuller example.

Answer 2

I have another way to convert this content. Using Underscore.js to make the code more readable. Here is the example:

var content = {
    "items": [{
        "id": "02egnc0eo7qk53e9nh7igq6d48",
        "summary": "Learn to code",
        "start": {
            "dateTime": "2017-03-04T19:00:00+05:30"
        }
    }, {
        "id": "nj4h567r617n4vd4kq98qfjrek",
        "summary": "Modern Data Architectures for Business Insights at Scale Confirmation",
        "start": {
            "dateTime": "2017-03-07T11:30:00+05:30"
        }
    }]
};
var result = _.map(content.items, function(item) {
    return {
        id: item.id,
        title: item.summary,
        start: item.start.dateTime,
        description: ""
    };
});
console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js"></script>

The result as following:

[
  {
    "id": "02egnc0eo7qk53e9nh7igq6d48",
    "title": "Learn to code",
    "start": "2017-03-04T19:00:00+05:30",
    "description": ""
  },
  {
    "id": "nj4h567r617n4vd4kq98qfjrek",
    "title": "Modern Data Architectures for Business Insights at Scale Confirmation",
    "start": "2017-03-07T11:30:00+05:30",
    "description": ""
  }
]