[vtkusers] VTK-js: how to read a .json file

Wed Jul 26 10:12:23 EDT 2017

Hi Christina,

I think the issue is inside your JSON file which might not be properly
formed.
To make sure your file is properly formatted, you can use a service like
below to spot the issue quickly.

https://jsonlint.com/

Regarding the "require" or "import" method to ingest your file, they should
both work but we prefer to use the "import" syntax.

Seb

On Wed, Jul 26, 2017 at 7:35 AM, Aron Helser <aron.helser at kitware.com>
wrote:

> Hi Cristina,
> I think the 'require' function may be the problem - in vtk-js and
> ParaViewWeb, we typically use 'import', like this:
>
> import localPresetImages from '../../presets.json';
>
> Try it that way?
> Regards,
> Aron
>
> On Wed, Jul 26, 2017 at 5:31 AM, Cristina Oyarzun <
> coyarzunlaura at googlemail.com> wrote:
>
>> Dear Scott and Aron,
>>
>> thank you for your answers. I was indeed using an older version of
>> Webpack, but I already upgraded to the newest version. Unfortunately I keep
>> getting errors when I try to read the JSON file. To this I have to add that
>> although I have been using vtk for quite a long time now, I am completely
>> new to javascript.
>>
>> If I understood correctly with webpack 2 I do not need to add anything to
>> the webpack.config.js to be able to read json files in the index.js. Is
>> this right? However, I try to read the json file with the following command
>> in index.js:
>>
>> const json = require('./file.json');
>>
>> apart of that line of code I didnt write anything else related to the json file. I got the following error:
>>
>> ERROR in ./src/file.json
>> Module build failed: SyntaxError: Unexpected token / in JSON at position 146
>>     at Object.parse (native)
>>     at Object.module.exports (D:\VTK-JS\node_modules\json-loader\index.js:4:
>> 49)
>>  @ ./src/index.js 285:13-35
>>  @ ./src/index.js
>>  @ multi (webpack)-dev-server/client?http://localhost:8080 ./src/index.js
>> webpack: Failed to compile.
>>
>> Thank you very much!!!
>>
>> Cristina
>>
>>
>>
>> On Fri, Jul 21, 2017 at 5:50 PM, Scott Wittenburg <
>> scott.wittenburg at kitware.com> wrote:
>>
>>> Hi Cristina,
>>>
>>> In vtk.js we now use webpack2 (in master at least, you may have picked
>>> an older version though), and the webpack2 documentation states that you no
>>> longer need a loader for json:
>>>
>>> https://webpack.js.org/guides/migrating/#json-loader-is-not-
>>> required-anymore
>>>
>>> Is your project also using webpack2?  In that case you shouldn't need
>>> the json loader.  Also, when you refer to "Build-in modules of Node.js",
>>> does that refer specifically to this:
>>>
>>> https://github.com/sindresorhus/builtin-modules
>>>
>>> or do you mean something else?
>>>
>>> Cheers,
>>> Scott
>>>
>>> On Fri, Jul 21, 2017 at 8:57 AM, Aron Helser <aron.helser at kitware.com>
>>> wrote:
>>>
>>>> Hi Cristina,
>>>> ParaViewWeb uses this webpack 1.x loader:
>>>> {
>>>>     test: /\.json$/,
>>>>     loader: 'json-loader',
>>>>   },
>>>> That should allow you to 'include' a json file in your javascript, and
>>>> then you might need to use the built-in JSON.parse() to turn it into an
>>>> object.
>>>>
>>>> Regards,
>>>> Aron
>>>>
>>>> On Fri, Jul 21, 2017 at 4:43 AM, Cristina Oyarzun via vtkusers <
>>>> vtkusers at vtk.org> wrote:
>>>>
>>>>> Dear all,
>>>>>
>>>>> I visualized several actors using VTK-js. Now I want to read a .json
>>>>> file and according to the information that it is included there assign
>>>>> different colors to the actors.
>>>>>
>>>>> Unfortunately as soon as I try to use the Build-in modules of Node.js
>>>>> I start getting errors. I didnt manage to find out how do I have to adapt
>>>>> the "webpack.config.js" (or the "package.json"?) so that it works.
>>>>>
>>>>> I found somewhere in a forum that it should work by adding " target:
>>>>> 'node' " to the webpack.config.js but it didnt. Any help would be great!
>>>>>
>>>>> Thank you!
>>>>> Cristina
>>>>>
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>>>>>
>>>>
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>>>
>>
>
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