index.ts

import {
  JupyterLab, JupyterLabPlugin
} from '@jupyterlab/application';

import {
  ICommandPalette
} from '@jupyterlab/apputils';

import {
  INotebookTracker
} from '@jupyterlab/notebook';

import '../style/index.css';

interface JupytextSection {
  formats?: string;
}

const JUPYTEXT_FORMATS = [
  {
    'formats': 'ipynb,auto:light',
    'label': 'Pair Notebook with light Script'
  },
  {
    'formats': 'ipynb,auto:percent',
    'label': 'Pair Notebook with percent Script'
  },
  {
    'formats': 'ipynb,auto:hydrogen',
    'label': 'Pair Notebook with hydrogen Script'
  },
  {
    'formats': 'ipynb,md',
    'label': 'Pair Notebook with Markdown'
  },
  {
    'formats': 'ipynb,Rmd',
    'label': 'Pair Notebook with R Markdown'
  },
  {
    'formats': 'custom',
    'label': 'Custom pairing'
  },
  {
    'formats': 'none',
    'label': 'Unpair Notebook'
  }
]

/**
 * Initialization data for the jupyterlab-jupytext extension.
 */
const extension: JupyterLabPlugin<void> = {
  id: 'jupyterlab-jupytext',
  autoStart: true,
  requires: [ICommandPalette, INotebookTracker],
  activate: (app: JupyterLab, palette: ICommandPalette, notebook_tracker: INotebookTracker) => {
    console.log('JupyterLab extension jupyterlab-jupytext is activated');

    // Jupytext formats
    JUPYTEXT_FORMATS.forEach((args, rank) => {
      const formats: string = args['formats']
      const command: string = 'jupytext:' + formats
      app.commands.addCommand(command, {
        label: args['label'],
        isToggled: () => {
          if (!notebook_tracker.currentWidget)
            return false;

          if (!notebook_tracker.currentWidget.context.model.metadata.has('jupytext'))
            return formats == 'none';

          const jupytext: JupytextSection = notebook_tracker.currentWidget.context.model.metadata.get('jupytext') as unknown as JupytextSection;
          if (!jupytext.formats)
            return formats == 'none'

          if (formats == 'custom')
            return (jupytext.formats && ['ipynb,auto:light', 'ipynb,auto:percent', 'ipynb,auto:hydrogen', 'ipynb,md', 'ipynb,Rmd'].indexOf(jupytext.formats) < 0)

          return jupytext.formats == formats
        },
        execute: () => {
          console.log('Jupytext: executing command=' + command)
          if (formats == 'custom') {
            alert("Please edit the notebook metadata directly if you wish a custom configuration.")
            return
          }

          const jupytext: JupytextSection = notebook_tracker.currentWidget.context.model.metadata.get('jupytext') as unknown as JupytextSection;

          if (formats == 'none') {
            if (!notebook_tracker.currentWidget.context.model.metadata.has('jupytext'))
              return

            if (jupytext.formats) {
              delete jupytext.formats
            }

            // TODO: This is always true! How can we check that the JupytextSection is really empty, ie. no other
            // field like 'comment_magics', 'split_at_heading', etc...
            if (jupytext == {})
              notebook_tracker.currentWidget.context.model.metadata.delete('jupytext')
            return
          }

          // set desired format
          if (jupytext)
            jupytext.formats = formats
          else
            notebook_tracker.currentWidget.context.model.metadata.set('jupytext', { formats })
        }
      });

      console.log('Jupytext: adding command=' + command + ' with rank=' + rank)
      palette.addItem({ command, rank, category: 'Jupytext' });
    })

    // Jupytext README
    palette.addItem({
      args: {
        'text': 'Jupytext Reference',
        'url': 'https://jupytext.readthedocs.io/en/latest/'
      }, command: 'help:open', category: 'Jupytext', rank: JUPYTEXT_FORMATS.length
    });
  }
};

export default extension;