47

I need some help with this error:

Uncaught SyntaxError: Unexpected end of JSON input
  at JSON.parse (<anonymous>)
  at Object.success (dashboard.js:22)
  at fire (jquery-3.3.1.js:3268)
  at Object.fireWith [as resolveWith] (jquery-3.3.1.js:3398)
  at done (jquery-3.3.1.js:9305)
  at XMLHttpRequest.<anonymous> (jquery-3.3.1.js:9548)

I was trying to transform a string to a JSON object using JSON.parse() which caused the above error. I am using oracleJet and this is my code:

function DashboardViewModel() {
      
    var self = this;
    self.lineTypeValue = ko.observable('curved');
    var scatterSeries = []; 
        
    $.getJSON( "http://localhost:8080/points", function (data) {
        console.info(data);
        var ch = '{"name":"graphe1","items":'+JSON.stringify(data.results[1])+ '}';
        console.info(ch);
        console.info(JSON.parse(scatterSeries));
        scatterSeries.push(JSON.parse(ch));           
    });

    /* chart data */
        
    this.scatterSeriesValue = ko.observableArray(scatterSeries);
        
    self.lineTypeOptions = [
        {id: 'straight', label: 'straight'},
        {id: 'curved', label: 'curved'},
        {id: 'stepped', label: 'stepped'},
        {id: 'segmented', label: 'segmented'},
        {id: 'none', label: 'none'}
    ];
}

The JSON that I got from "http://localhost:8080/points" looked like this:

{
  "results": [
    [
      {
        "b": "0.110547334",
        "cost": "0.000000",
        "w": "1.998889"
      }
    ],
    [
      {
        "x": 0,
        "y": 0
      },
      {
        "x": 1,
        "y": 2
      },
      {
        "x": 2,
        "y": 4
      },
      {
        "x": 3,
        "y": 6
      },
      {
        "x": 4,
        "y": 8
      },
      {
        "x": 5,
        "y": 10
      },
      {
        "x": 6,
        "y": 12
      },
      {
        "x": 7,
        "y": 14
      },
      {
        "x": 8,
        "y": 16
      },
      {
        "x": 9,
        "y": 18
      },
      {
        "x": 10,
        "y": 20
      },
      {
        "x": 11,
        "y": 22
      },
      {
        "x": 12,
        "y": 24
      },
      {
        "x": 13,
        "y": 26
      },
      {
        "x": 14,
        "y": 28
      },
      {
        "x": 15,
        "y": 30
      },
      {
        "x": 16,
        "y": 32
      },
      {
        "x": 17,
        "y": 34
      },
      {
        "x": 18,
        "y": 36
      },
      {
        "x": 19,
        "y": 38
      },
      {
        "x": 20,
        "y": 40
      },
      {
        "x": 21,
        "y": 42
      },
      {
        "x": 22,
        "y": 44
      },
      {
        "x": 23,
        "y": 46
      },
      {
        "x": 24,
        "y": 48
      },
      {
        "x": 25,
        "y": 50
      },
      {
        "x": 26,
        "y": 52
      },
      {
        "x": 27,
        "y": 54
      },
      {
        "x": 28,
        "y": 56
      },
      {
        "x": 29,
        "y": 58
      },
      {
        "x": 30,
        "y": 60
      },
      {
        "x": 31,
        "y": 62
      },
      {
        "x": 32,
        "y": 64
      },
      {
        "x": 33,
        "y": 66
      },
      {
        "x": 34,
        "y": 68
      },
      {
        "x": 35,
        "y": 70
      },
      {
        "x": 36,
        "y": 72
      },
      {
        "x": 37,
        "y": 74
      },
      {
        "x": 38,
        "y": 76
      },
      {
        "x": 39,
        "y": 78
      },
      {
        "x": 40,
        "y": 80
      },
      {
        "x": 41,
        "y": 82
      },
      {
        "x": 42,
        "y": 84
      },
      {
        "x": 43,
        "y": 86
      },
      {
        "x": 44,
        "y": 88
      },
      {
        "x": 45,
        "y": 90
      },
      {
        "x": 46,
        "y": 92
      },
      {
        "x": 47,
        "y": 94
      },
      {
        "x": 48,
        "y": 96
      },
      {
        "x": 49,
        "y": 98
      },
      {
        "x": 50,
        "y": 100
      },
      {
        "x": 51,
        "y": 102
      },
      {
        "x": 52,
        "y": 104
      },
      {
        "x": 53,
        "y": 106
      },
      {
        "x": 54,
        "y": 108
      },
      {
        "x": 55,
        "y": 110
      },
      {
        "x": 56,
        "y": 112
      },
      {
        "x": 57,
        "y": 114
      },
      {
        "x": 58,
        "y": 116
      },
      {
        "x": 59,
        "y": 118
      },
      {
        "x": 60,
        "y": 120
      },
      {
        "x": 61,
        "y": 122
      },
      {
        "x": 62,
        "y": 124
      },
      {
        "x": 63,
        "y": 126
      },
      {
        "x": 64,
        "y": 128
      },
      {
        "x": 65,
        "y": 130
      },
      {
        "x": 66,
        "y": 132
      },
      {
        "x": 67,
        "y": 134
      },
      {
        "x": 68,
        "y": 136
      },
      {
        "x": 69,
        "y": 138
      },
      {
        "x": 70,
        "y": 140
      },
      {
        "x": 71,
        "y": 142
      },
      {
        "x": 72,
        "y": 144
      },
      {
        "x": 73,
        "y": 146
      },
      {
        "x": 74,
        "y": 148
      },
      {
        "x": 75,
        "y": 150
      },
      {
        "x": 76,
        "y": 152
      },
      {
        "x": 77,
        "y": 154
      },
      {
        "x": 78,
        "y": 156
      },
      {
        "x": 79,
        "y": 158
      },
      {
        "x": 80,
        "y": 160
      },
      {
        "x": 81,
        "y": 162
      },
      {
        "x": 82,
        "y": 164
      },
      {
        "x": 83,
        "y": 166
      },
      {
        "x": 84,
        "y": 168
      },
      {
        "x": 85,
        "y": 170
      },
      {
        "x": 86,
        "y": 172
      },
      {
        "x": 87,
        "y": 174
      },
      {
        "x": 88,
        "y": 176
      },
      {
        "x": 89,
        "y": 178
      },
      {
        "x": 90,
        "y": 180
      },
      {
        "x": 91,
        "y": 182
      },
      {
        "x": 92,
        "y": 184
      },
      {
        "x": 93,
        "y": 186
      },
      {
        "x": 94,
        "y": 188
      },
      {
        "x": 95,
        "y": 190
      },
      {
        "x": 96,
        "y": 192
      },
      {
        "x": 97,
        "y": 194
      },
      {
        "x": 98,
        "y": 196
      },
      {
        "x": 99,
        "y": 198
      }
    ]
  ]
}

and I wanted the variable scatterSeries to hold a table like this one:

[
  {
    name: "graphe1",
    items: [
      {
        x: 8,
        y: 2
      },
      {
        x: 15,
        y: 15
      },
      {
        x: 25,
        y: 26
      },
      {
        x: 33,
        y: 22
      },
      {
        x: 36,
        y: 40
      }
    ]
  }
]

I got the string ch in the console:

{
  "name": "graphe1",
  "items": [
    {
      "x": 0,
      "y": 0
    },
    {
      "x": 1,
      "y": 2
    },
    {
      "x": 2,
      "y": 4
    },
    {
      "x": 3,
      "y": 6
    },
    {
      "x": 4,
      "y": 8
    },
    {
      "x": 5,
      "y": 10
    },
    {
      "x": 6,
      "y": 12
    },
    {
      "x": 7,
      "y": 14
    },
    {
      "x": 8,
      "y": 16
    },
    {
      "x": 9,
      "y": 18
    },
    {
      "x": 10,
      "y": 20
    },
    {
      "x": 11,
      "y": 22
    },
    {
      "x": 12,
      "y": 24
    },
    {
      "x": 13,
      "y": 26
    },
    {
      "x": 14,
      "y": 28
    },
    {
      "x": 15,
      "y": 30
    },
    {
      "x": 16,
      "y": 32
    },
    {
      "x": 17,
      "y": 34
    },
    {
      "x": 18,
      "y": 36
    },
    {
      "x": 19,
      "y": 38
    },
    {
      "x": 20,
      "y": 40
    },
    {
      "x": 21,
      "y": 42
    },
    {
      "x": 22,
      "y": 44
    },
    {
      "x": 23,
      "y": 46
    },
    {
      "x": 24,
      "y": 48
    },
    {
      "x": 25,
      "y": 50
    },
    {
      "x": 26,
      "y": 52
    },
    {
      "x": 27,
      "y": 54
    },
    {
      "x": 28,
      "y": 56
    },
    {
      "x": 29,
      "y": 58
    },
    {
      "x": 30,
      "y": 60
    },
    {
      "x": 31,
      "y": 62
    },
    {
      "x": 32,
      "y": 64
    },
    {
      "x": 33,
      "y": 66
    },
    {
      "x": 34,
      "y": 68
    },
    {
      "x": 35,
      "y": 70
    },
    {
      "x": 36,
      "y": 72
    },
    {
      "x": 37,
      "y": 74
    },
    {
      "x": 38,
      "y": 76
    },
    {
      "x": 39,
      "y": 78
    },
    {
      "x": 40,
      "y": 80
    },
    {
      "x": 41,
      "y": 82
    },
    {
      "x": 42,
      "y": 84
    },
    {
      "x": 43,
      "y": 86
    },
    {
      "x": 44,
      "y": 88
    },
    {
      "x": 45,
      "y": 90
    },
    {
      "x": 46,
      "y": 92
    },
    {
      "x": 47,
      "y": 94
    },
    {
      "x": 48,
      "y": 96
    },
    {
      "x": 49,
      "y": 98
    },
    {
      "x": 50,
      "y": 100
    },
    {
      "x": 51,
      "y": 102
    },
    {
      "x": 52,
      "y": 104
    },
    {
      "x": 53,
      "y": 106
    },
    {
      "x": 54,
      "y": 108
    },
    {
      "x": 55,
      "y": 110
    },
    {
      "x": 56,
      "y": 112
    },
    {
      "x": 57,
      "y": 114
    },
    {
      "x": 58,
      "y": 116
    },
    {
      "x": 59,
      "y": 118
    },
    {
      "x": 60,
      "y": 120
    },
    {
      "x": 61,
      "y": 122
    },
    {
      "x": 62,
      "y": 124
    },
    {
      "x": 63,
      "y": 126
    },
    {
      "x": 64,
      "y": 128
    },
    {
      "x": 65,
      "y": 130
    },
    {
      "x": 66,
      "y": 132
    },
    {
      "x": 67,
      "y": 134
    },
    {
      "x": 68,
      "y": 136
    },
    {
      "x": 69,
      "y": 138
    },
    {
      "x": 70,
      "y": 140
    },
    {
      "x": 71,
      "y": 142
    },
    {
      "x": 72,
      "y": 144
    },
    {
      "x": 73,
      "y": 146
    },
    {
      "x": 74,
      "y": 148
    },
    {
      "x": 75,
      "y": 150
    },
    {
      "x": 76,
      "y": 152
    },
    {
      "x": 77,
      "y": 154
    },
    {
      "x": 78,
      "y": 156
    },
    {
      "x": 79,
      "y": 158
    },
    {
      "x": 80,
      "y": 160
    },
    {
      "x": 81,
      "y": 162
    },
    {
      "x": 82,
      "y": 164
    },
    {
      "x": 83,
      "y": 166
    },
    {
      "x": 84,
      "y": 168
    },
    {
      "x": 85,
      "y": 170
    },
    {
      "x": 86,
      "y": 172
    },
    {
      "x": 87,
      "y": 174
    },
    {
      "x": 88,
      "y": 176
    },
    {
      "x": 89,
      "y": 178
    },
    {
      "x": 90,
      "y": 180
    },
    {
      "x": 91,
      "y": 182
    },
    {
      "x": 92,
      "y": 184
    },
    {
      "x": 93,
      "y": 186
    },
    {
      "x": 94,
      "y": 188
    },
    {
      "x": 95,
      "y": 190
    },
    {
      "x": 96,
      "y": 192
    },
    {
      "x": 97,
      "y": 194
    },
    {
      "x": 98,
      "y": 196
    },
    {
      "x": 99,
      "y": 198
    }
  ]
}

Any help?

8 Answers 8

53

You are calling:

JSON.parse(scatterSeries)

But when you defined scatterSeries, you said:

var scatterSeries = []; 

When you try to parse it as JSON it is converted to a string (""), which is empty, so you reach the end of the string before having any of the possible content of a JSON text.

scatterSeries is not JSON. Do not try to parse it as JSON.

data is not JSON either (getJSON will parse it as JSON automatically).

ch is JSON … but shouldn't be. You should just create a plain object in the first place:

var ch = {
    "name": "graphe1",
    "items": data.results[1]
};

scatterSeries.push(ch);

In short, for what you are doing, you shouldn't have JSON.parse anywhere in your code. The only place it should be is in the jQuery library itself.

Sign up to request clarification or add additional context in comments.

Comments

9

I was trying to debug this same error (I was writing code in TypeScript), but no matter what I did, the error didn't go away, it was really persistent.

I tried to look into the solution in many blogs and also this SO thread. I tried everything and nothing worked out.

Finally, I saw that I created the required file named products.json in which I gave a single extra newline (meaning, previously the file had 1 empty line, now it had 2 empty lines) and was following good GitHub practices as mentioned here.

Because of that single extra newline in my products.json file, I wasted 2 hours fixing a bug that didn't exist in the first place.

Finally when I deleted the entire products.json file and re-ran the entire thing, I didn't get any runtime errors and everything was running without any problems.

What I learned by going through all this? It's that experience is the teacher of all things.

Comments

5

Encountered this error in the following function when I tried to pull 'nothing' from LS

Quick fix for posterity

const getUserFromLocalStorage = () => {
    try {
        return JSON.parse(localStorage.getItem('user') || '');
    } catch (error) {
        return null;
    }
};

Comments

1

Remove this line from your code:

console.info(JSON.parse(scatterSeries));

Comments

0

Issue is with the Json.parse of empty array - scatterSeries , as you doing console log of scatterSeries before pushing ch

var data = { "results":[  
  [  
     {  
        "b":"0.110547334",
        "cost":"0.000000",
        "w":"1.998889"
     }
  ],
  [  
     {  
        "x":0,
        "y":0
     },
     {  
        "x":1,
        "y":2
     },
     {  
        "x":2,
        "y":4
     },
     {  
        "x":3,
        "y":6
     },
     {  
        "x":4,
        "y":8
     },
     {  
        "x":5,
        "y":10
     },
     {  
        "x":6,
        "y":12
     },
     {  
        "x":7,
        "y":14
     },
     {  
        "x":8,
        "y":16
     },
     {  
        "x":9,
        "y":18
     },
     {  
        "x":10,
        "y":20
     },
     {  
        "x":11,
        "y":22
     },
     {  
        "x":12,
        "y":24
     },
     {  
        "x":13,
        "y":26
     },
     {  
        "x":14,
        "y":28
     },
     {  
        "x":15,
        "y":30
     },
     {  
        "x":16,
        "y":32
     },
     {  
        "x":17,
        "y":34
     },
     {  
        "x":18,
        "y":36
     },
     {  
        "x":19,
        "y":38
     },
     {  
        "x":20,
        "y":40
     },
     {  
        "x":21,
        "y":42
     },
     {  
        "x":22,
        "y":44
     },
     {  
        "x":23,
        "y":46
     },
     {  
        "x":24,
        "y":48
     },
     {  
        "x":25,
        "y":50
     },
     {  
        "x":26,
        "y":52
     },
     {  
        "x":27,
        "y":54
     },
     {  
        "x":28,
        "y":56
     },
     {  
        "x":29,
        "y":58
     },
     {  
        "x":30,
        "y":60
     },
     {  
        "x":31,
        "y":62
     },
     {  
        "x":32,
        "y":64
     },
     {  
        "x":33,
        "y":66
     },
     {  
        "x":34,
        "y":68
     },
     {  
        "x":35,
        "y":70
     },
     {  
        "x":36,
        "y":72
     },
     {  
        "x":37,
        "y":74
     },
     {  
        "x":38,
        "y":76
     },
     {  
        "x":39,
        "y":78
     },
     {  
        "x":40,
        "y":80
     },
     {  
        "x":41,
        "y":82
     },
     {  
        "x":42,
        "y":84
     },
     {  
        "x":43,
        "y":86
     },
     {  
        "x":44,
        "y":88
     },
     {  
        "x":45,
        "y":90
     },
     {  
        "x":46,
        "y":92
     },
     {  
        "x":47,
        "y":94
     },
     {  
        "x":48,
        "y":96
     },
     {  
        "x":49,
        "y":98
     },
     {  
        "x":50,
        "y":100
     },
     {  
        "x":51,
        "y":102
     },
     {  
        "x":52,
        "y":104
     },
     {  
        "x":53,
        "y":106
     },
     {  
        "x":54,
        "y":108
     },
     {  
        "x":55,
        "y":110
     },
     {  
        "x":56,
        "y":112
     },
     {  
        "x":57,
        "y":114
     },
     {  
        "x":58,
        "y":116
     },
     {  
        "x":59,
        "y":118
     },
     {  
        "x":60,
        "y":120
     },
     {  
        "x":61,
        "y":122
     },
     {  
        "x":62,
        "y":124
     },
     {  
        "x":63,
        "y":126
     },
     {  
        "x":64,
        "y":128
     },
     {  
        "x":65,
        "y":130
     },
     {  
        "x":66,
        "y":132
     },
     {  
        "x":67,
        "y":134
     },
     {  
        "x":68,
        "y":136
     },
     {  
        "x":69,
        "y":138
     },
     {  
        "x":70,
        "y":140
     },
     {  
        "x":71,
        "y":142
     },
     {  
        "x":72,
        "y":144
     },
     {  
        "x":73,
        "y":146
     },
     {  
        "x":74,
        "y":148
     },
     {  
        "x":75,
        "y":150
     },
     {  
        "x":76,
        "y":152
     },
     {  
        "x":77,
        "y":154
     },
     {  
        "x":78,
        "y":156
     },
     {  
        "x":79,
        "y":158
     },
     {  
        "x":80,
        "y":160
     },
     {  
        "x":81,
        "y":162
     },
     {  
        "x":82,
        "y":164
     },
     {  
        "x":83,
        "y":166
     },
     {  
        "x":84,
        "y":168
     },
     {  
        "x":85,
        "y":170
     },
     {  
        "x":86,
        "y":172
     },
     {  
        "x":87,
        "y":174
     },
     {  
        "x":88,
        "y":176
     },
     {  
        "x":89,
        "y":178
     },
     {  
        "x":90,
        "y":180
     },
     {  
        "x":91,
        "y":182
     },
     {  
        "x":92,
        "y":184
     },
     {  
        "x":93,
        "y":186
     },
     {  
        "x":94,
        "y":188
     },
     {  
        "x":95,
        "y":190
     },
     {  
        "x":96,
        "y":192
     },
     {  
        "x":97,
        "y":194
     },
     {  
        "x":98,
        "y":196
     },
     {  
        "x":99,
        "y":198
     }
  ]]};

var scatterSeries = []; 

var ch = '{"name":"graphe1","items":'+JSON.stringify(data.results[1])+ '}';
               console.info(ch);
               
               scatterSeries.push(JSON.parse(ch));
console.info(scatterSeries);

code sample - https://codepen.io/nagasai/pen/GGzZVB

Comments

0

You define var scatterSeries = [];, and then try to parse it as a json string at console.info(JSON.parse(scatterSeries)); which obviously fails. The variable is converted to an empty string, which causes an "unexpected end of input" error when trying to parse it.

Comments

0

In my case, using .NET 6, the problem was that the controller was declared as void and did not return any value.

Simply changing the method declaration to int and adding return 0; solved this issue for me.

[HttpPost]
public int MyMethod(string text)
{
    _logger.Log(text);
    return 0;
}

Comments

-1

This is because of the data that you are trying to parse is not in a parsable format . so i suggest to check the data is parsable or not before define the parse.

const IsParsable = (data) => {
            try {
                  JSON.parse(data);
                 } catch (e) {
                  return false;
                }
             return true;
    }
        
    var Obj= JSON.stringify({
                "name": "graphe1",
               "items": data.results[1]
     })

    return  IsParsable (Obj) ?  JSON.parse(Obj) : false

Comments

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