JavaScript: Parse JSON with dynamic key values

Question

I have a JSON as below and I want to extract data from columns and rows array from it.

{
  "id":0,
  "tabName":"newtab",
  "columns":[
    {
      "id":0,
      "name":"firstname",
      "type":"entity",
      "operator":"=",
      "$$hashKey":"object:40"
    },
    {
      "id":1,
      "name":"address",
      "type":"domain",
      "operator":"<",
      "$$hashKey":"object:50"
    }
  ],
"rows":[
  {
    "0":"Adam", //this first row data corresponds to "Name" column
    "1":"5432 River Drive", //this first row data corresponds to "Address" column
    "$$hashKey":"object:34",
    "tabId":"1122", 
    "description":"New Tab",
    "id":1
  },
  {
    "0":"Silver",  //this 2nd row data corresponds to "Name" column
    "1":"Address 2", //this 2nd row data corresponds to "Address" column
    "$$hashKey":"object:53",
    "tabId":"2345",
    "description":"New 2nd Tab",
    "id":2
  }
],
"uniqueIdCounter":3
}

From the above JSON, I want to extract columns and rows values. This is just sample JSON and the actual one can have more column and rows entries.

In the columns array: id, name, type operator keys remain the same for every column entry.

In the rows array: tabid, description and id keys remain the same for every row entry.

The issue with the row array is the key values "0", "1" (that actually correspond to columns firstname & address). How to loop through this array and extract these dynamic values? By dynamic I mean if I have more than 2 rows, the keys in the rows would be "0", "1", "2" and so on for other rows.

I started with writing this loop:

var jsonColumns = JSON.parse(JSON.stringify($scope.myTable.columns));
for (var i = 0; i < jsonColumns.length; i++) {
    var obj = jsonColumns[i]; 
    //For columns data I can do obj.id, obj.name etc and works fine
}

For rows I am not sure how to proceed here:

var jsonRows = JSON.parse(JSON.stringify($scope.myTable.rows));
for (var i = 0; i < jsonRows.length; i++) {
    var obj = jsonRows[i]; 
    //How can I extract rows with keys "0", "1" where I dont know these key names in advance
}

Any inputs to this, please? Thanks

you can do Object.getOwnPropertyNames(jsonRows[i]) to get all the keys. — D. Seah
– D. Seah, Commented Jul 18, 2018 at 3:36

Senal · Accepted Answer · 2018-07-18 05:31:25Z

Assuming that the tabid, description, id and $$hashKey are static, you can extract those dynamic keys as follows,

let tableObj = {
  "id":0,
  "tabName":"newtab",
  "columns":[
    {
      "id":0,
      "name":"firstname",
      "type":"entity",
      "operator":"=",
      "$$hashKey":"object:40"
    },
    {
      "id":1,
      "name":"address",
      "type":"domain",
      "operator":"<",
      "$$hashKey":"object:50"
    }
  ],
"rows":[
  {
    "0":"Adam", //this first row data corresponds to "Name" column
    "1":"5432 River Drive", //this first row data corresponds to "Address" column
    "$$hashKey":"object:34",
    "tabId":"1122", 
    "description":"New Tab",
    "id":1
  },
  {
    "0":"Silver",  //this 2nd row data corresponds to "Name" column
    "1":"Address 2", //this 2nd row data corresponds to "Address" column
    "$$hashKey":"object:53",
    "tabId":"2345",
    "description":"New 2nd Tab",
    "id":2
  }
],
"uniqueIdCounter":3
};

let jsonRows = JSON.parse(JSON.stringify(tableObj.rows));
let staticAttributes = ['tabId', 'description', 'id', '$$hashKey'];
let extractedData = [];
for (const obj of jsonRows) {
    let extractedObj = {};
    
    for (let key in obj) {
      if (obj.hasOwnProperty(key) && !staticAttributes.includes(key)) {
        extractedObj[key] = obj[key];
      }
    }
    
    extractedData.push(extractedObj);
}

console.log(extractedData);

Sanoj_V · Accepted Answer · 2018-07-18 05:41:03Z

0

You can extract key like this:

var jsonRows = JSON.parse(JSON.stringify($scope.myTable.rows));
for (var i = 0; i < jsonRows.length; i++) {
     var obj = jsonRows[i]; 
     console.log("Rows", obj["0"], obj["1"], obj["id"], obj["tabId"], obj["description"]); //here you can extract data with specified keys
}

Rest of your code will same.

edited Jul 18, 2018 at 5:41

answered Jul 18, 2018 at 5:34

Sanoj_V

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Comments

Tarun Khurana · Accepted Answer · 2018-07-18 05:42:24Z

0

Use for each loop for it :

var jsonData = {
    data: [{
        "key1": 1,
        "key2": 2
    }, {
        "key1": 3,
        "key2": 4
    }]
}
for (var index in jsonData.data) {
    for (var key in jsonData.data[index]) {
        console.log(key)
    }
}

answered Jul 18, 2018 at 5:42

Tarun Khurana

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