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

[Aron Helser]

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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