javascript convert JSON string to JSON object

Question

I al using javascript and looping through the values of a submitted form and trying to build a son object out of the form values.

This is an example of the final object I need:

{
  "DataObject": {
    "user": { "-name": "username" },
    "contentFile": {
      "-filename": "Breaking_News",
      "lock": { "-fileIsBeingEdited": "false" },
      "content": {
        "line": [
          {
            "-index": "1",
            "-text": "this is the header"
          },
          {
            "-index": "2",
            "-text": "this is the first line"
          },
          {
            "-index": "3",
            "-text": "this is the second line"
          }
        ]
      }
    }
  }
}

So far i am adding all of this data to a string as that seems to be the only way i can insert the form values (the line array) into the middle of the object.

var jsonStr = '{'
       + 'iceteaDataObject: {'
        + 'user: {"-name": "hindsc52"},'
          + 'contentFile: {'
          + '"-filename": "Ticker",'
          + 'lock: { "-fileIsBeingEdited": "false" },'
          + 'content: {'
          +  'line: ['

    for(var i = 0; i < elem.length; i++) {
      if(!elem[i].value == '') {
        jsonStr += '{'
        jsonStr += "-index: " + i + ',';
        jsonStr += "-text: " + elem[i].value;
        jsonStr += '},'
      }
    }

    jsonStr += ']}}}}';

    console.log(JSON.parse(jsonData));

however when running this I get the error: unexpected token 'i'.

I have tried to use stringily but then just outputs the entire sting again.

Check the format of string, it's incorrect. Paste the code in JSONLint and see errors — Tushar
– Tushar, Commented Oct 15, 2015 at 11:10
You need an extra ; right before the for loop as your first instruction is not ended due to the lack of it. — Laurent S.
– Laurent S., Commented Oct 15, 2015 at 11:11
You shouldn't create a JSON string that way. It will fail if the value of the form field contains ", beside that keys in JSON format need to be quoted by " so you don't create a valid JSON string at all. The unexpected i is because of your key iceteaDataObject that is not quoted. Create a normal JavaScript object and use JSON.stringify — t.niese
– t.niese, Commented Oct 15, 2015 at 11:12

T.J. Crowder · Accepted Answer · 2015-10-15 11:15:29Z

You don't need or want JSON for this, just build the object:

// Sample data
var elem = [{
  value: "one"
}, {
  value: "two"
}];

// Build the object
var obj = {
  "DataObject": {
    "user": {
      "-name": "username"
    },
    "contentFile": {
      "-filename": "Breaking_News",
      "lock": {
        "-fileIsBeingEdited": "false"
      },
      "content": {
        "line": []
      }
    }
  }
};
var line = obj.DataObject.contentFile.content.line;
elem.forEach(function(entry, index) {
  if (entry.value != '') {
    line.push({
      "-index": index,
      "-text": entry.value
    });
  }
});

// Show result:
document.body.innerHTML =
  "<pre>" +
  JSON.stringify(obj, null, 2) +
  "</pre>";

Side note: You don't check for blank strings like this:

if (!entry.value == '') { // <== Incorrect

You can use:

if (entry.value != '') {

or:

if (entry.value) {

n00dl3 · Accepted Answer · 2015-10-15 11:14:15Z

0

You shouldn't build JSON like this, but use JSON.stringify() (see MDN doc) instead:

var myObject={foo:"bar"};
var myJSON=JSON.stringify(myObject);
console.log(myJSON); //echo {"foo":"bar"}

answered Oct 15, 2015 at 11:14

n00dl3

21.6k8 gold badges70 silver badges77 bronze badges

Comments

user405398 · Accepted Answer · 2015-10-15 11:17:45Z

0

Here is an alternative way:

var json = {
  iceteaDataObject: {
    "-name": "hindsc52"
  },
  contentFile: {
    "-filename": "Ticker",
    lock: { "-fileIsBeingEdited": "false" },
    content: {line: []}
  }
}
for(var i = 0; i < elem.length; i++) {
      if(!elem[i].value == '') {
        json.contentFile.content.line.push({"-index": i,"-text": elem[i].value }
      }
    }
var jsonStr = JSON.stringify(json);

answered Oct 15, 2015 at 11:17

user405398

Comments

Eugen Timm · Accepted Answer · 2015-10-15 11:20:20Z

0

You need to put all your keys in quotes for this to work. As the others have pointed out though, you are not really supposed to do this.

If you still want to do it your way, try this:

var jsonStr = '{'
      + '"iceteaDataObject": {'
      + '"user": {"-name": "hindsc52"},'
      + '"contentFile": {'
      + '"-filename": "Ticker",'
      + '"lock": { "-fileIsBeingEdited": "false" },'
      + '"content": {'
      +  '"line": ['

for(var i = 0; i < elem.length; i++) {
  if(!elem[i].value == '') {
    jsonStr += '{'
    jsonStr += '"-index": ' + i + ',';
    jsonStr += '"-text": ' + '"' + elem[i].value + '"';
    jsonStr += '},'
  }
}

jsonStr += ']}}}}';

answered Oct 15, 2015 at 11:20

Eugen Timm

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