CODEWITHSUNDEEP
javascriptjsond3.js
lost
lost

Reputation: 377

D3.js d3.json returns Uncaught TypeError: Cannot read property '0' of undefined

I am do not know much about javascript or JSON and I am not sure why this is not working.

A level of my JSON is below, but it basically is 

[{'Africa' : {'children':[{stuff}], 'name':Africa} ...other continents

The pattern is always the same, where the a dict key is defined, in it is children and its name.

When I load it into d3.json, I get the error Uncaught TypeError: Cannot read property '0' of undefined. 

d3.json("data/output.json", function(error, json) {
  root = json[0];
  update(root);
});

What am I doing wrong? Is there a problem with my my json or do I need to add more detail in the d3.json function?

I generated my json in python like this

def build_tree(d, val):
    return [{id_:{'name': name, 'children': build_tree(d, id_)} for id_, name in d[val]}]

My JSON is this 

 [{'Africa': {'children': [{'Egypt': {'children': [{'EG-Cables': {'children': [{'H03VVH2F2x0.75mm': {'children': [{'2.5A/250V': {'children': [{}],
                                                                                                                                    'name': 'Max-Rating'}}],
                                                                                                        'name': 'Cables'},
                                                                                   'H05RRF3G1.0mm': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                                'name': 'Max-Rating'}}],
                                                                                                     'name': 'Cables'},
                                                                                   'H05VVF2x1.00mm': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                                 'name': 'Max-Rating'}}],
                                                                                                      'name': 'Cables'},
                                                                                   'H05VVF3G0.75mm': {'children': [{'2.5A/250V': {'children': [{}],
                                                                                                                                  'name': 'Max-Rating'}}],
                                                                                                      'name': 'Cables'},
                                                                                   'H05VVF3G1.0mm': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                                'name': 'Max-Rating'}}],
                                                                                                     'name': 'Cables'},
                                                                                   'H05VVF3G1.5mm': {'children': [{'16A/250V': {'children': [{}],
                                                                                                                                'name': 'Max-Rating'}}],
                                                                                                     'name': 'Cables'}}],
                                                                     'name': 'Products'},
                                                       'EG-Plug': {'children': [{'BS1363': {'children': [{'13A/V': {'children': [{}],
                                                                                                                    'name': 'Max-Rating'}}],
                                                                                            'name': 'Plug'},
                                                                                 'CEE-7/XVLL': {'children': [{'16A/250V': {'children': [{}],
                                                                                                                           'name': 'Max-Rating'}}],
                                                                                                'name': 'Plug'},
                                                                                 'CEE-XVLL': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                         'name': 'Max-Rating'}}],
                                                                                              'name': 'Plug'},
                                                                                 'EN-50075-XVL': {'children': [{'2.5A/250V': {'children': [{}],
                                                                                                                              'name': 'Max-Rating'}}],
                                                                                                  'name': 'Plug'}}],
                                                                   'name': 'Products'}}],
                                         'name': 'Country'},
                               'Nigeria': {'children': [{'NG-Cables': {'children': [{'H03VVH2F2x0.75mm': {'children': [{'2.5A/250V': {'children': [{}],
                                                                                                                                      'name': 'Max-Rating'}}],
                                                                                                          'name': 'Cables'},
                                                                                     'H05RRF3G1.0mm': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                                  'name': 'Max-Rating'}}],
                                                                                                       'name': 'Cables'},
                                                                                     'H05VVF2x1.00mm': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                                   'name': 'Max-Rating'}}],
                                                                                                        'name': 'Cables'},
                                                                                     'H05VVF3G0.75mm': {'children': [{'2.5A/250V': {'children': [{}],
                                                                                                                                    'name': 'Max-Rating'}}],
                                                                                                        'name': 'Cables'},
                                                                                     'H05VVF3G1.0mm': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                                  'name': 'Max-Rating'}}],
                                                                                                       'name': 'Cables'},
                                                                                     'H05VVF3G1.5mm': {'children': [{'16A/250V': {'children': [{}],
                                                                                                                                  'name': 'Max-Rating'}}],
                                                                                                       'name': 'Cables'}}],
                                                                       'name': 'Products'},
                                                         'NG-Plug': {'children': [{'BS1363': {'children': [{'13A/V': {'children': [{}],
                                                                                                                      'name': 'Max-Rating'}}],
                                                                                              'name': 'Plug'},
                                                                                   'SABS-164/1:1992': {'children': [{'16A/250V': {'children': [{}],
                                                                                                                                  'name': 'Max-Rating'}}],
                                                                                                       'name': 'Plug'}}],
                                                                     'name': 'Products'}}],
                                           'name': 'Country'},
                               'South-Africa': {'children': [{'ZA-Cables': {'children': [{'H03VVH2F2x0.75mm': {'children': [{'2.5A/250V': {'children': [{}],
                                                                                                                                           'name': 'Max-Rating'}}],
                                                                                                               'name': 'Cables'},
                                                                                          'H05RRF3G1.0mm': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                                       'name': 'Max-Rating'}}],
                                                                                                            'name': 'Cables'},
                                                                                          'H05VVF2x1.00mm': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                                        'name': 'Max-Rating'}}],
                                                                                                             'name': 'Cables'},
                                                                                          'H05VVF3G0.75mm': {'children': [{'2.5A/250V': {'children': [{}],
                                                                                                                                         'name': 'Max-Rating'}}],
                                                                                                             'name': 'Cables'},
                                                                                          'H05VVF3G1.0mm': {'children': [{'10A/250V': {'children': [{}],
                                                                                                                                       'name': 'Max-Rating'}}],
                                                                                                            'name': 'Cables'},
                                                                                          'H05VVF3G1.5mm': {'children': [{'16A/250V': {'children': [{}],
                                                                                                                                       'name': 'Max-Rating'}}],
                                                                                                            'name': 'Cables'}}],
                                                                            'name': 'Products'},
                                                              'ZA-Plug': {'children': [{'SABS-164/1:1992': {'children': [{'16A/250V': {'children': [{}],
                                                                                                                                       'name': 'Max-Rating'}}],
                                                                                                            'name': 'Plug'}}],
                                                                          'name': 'Products'}}],
                                                'name': 'Country'}}],
                 'name': 'Africa'},

Upvotes: 0

Views: 1129

Answers (1)

Oliver
Oliver

Reputation: 11597

There are several problems here. The root cause of your issue is a problem with the JSON you are passing to d3.js: it is incorrectly formed. I suggest using JSONLint to verify that data/output.json is in a correct format: http://jsonlint.com/.

In addition, you should check for parsing errors in the callback function when you read in the data. For instance, try writing something like this:

d3.json("data/output.json", function(error, json) {
    if (error) {
        console.log(error);
        alert(error); // I would suggest a more sophisticated UI that just 
                      // an alert box, but this suffices as an example.
    }
    else {
        root = json[0];
        update(root);
    }
});

Upvotes: 1

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