index.js

/*
 * Copyright (c) Jupyter Development Team.
 * Distributed under the terms of the Modified BSD License.
 */

import { PageConfig } from '@jupyterlab/coreutils';

import './style.js';

async function createModule(scope, module) {
  try {
    const factory = await window._JUPYTERLAB[scope].get(module);
    return factory();
  } catch(e) {
    console.warn(`Failed to create module: package: ${scope}; module: ${module}`);
    throw e;
  }
}

/**
 * The main entry point for the application.
 */
export async function main() {

   // Handle a browser test.
   // Set up error handling prior to loading extensions.
   var browserTest = PageConfig.getOption('browserTest');
   if (browserTest.toLowerCase() === 'true') {
     var el = document.createElement('div');
     el.id = 'browserTest';
     document.body.appendChild(el);
     el.textContent = '[]';
     el.style.display = 'none';
     var errors = [];
     var reported = false;
     var timeout = 25000;

     var report = function() {
       if (reported) {
         return;
       }
       reported = true;
       el.className = 'completed';
     }

     window.onerror = function(msg, url, line, col, error) {
       errors.push(String(error));
       el.textContent = JSON.stringify(errors)
     };
     console.error = function(message) {
       errors.push(String(message));
       el.textContent = JSON.stringify(errors)
     };
  }

  var JupyterLab = require('@jupyterlab/application').JupyterLab;
  var disabled = [];
  var deferred = [];
  var ignorePlugins = [];
  var register = [];


  const federatedExtensionPromises = [];
  const federatedMimeExtensionPromises = [];
  const federatedStylePromises = [];

  // Start initializing the federated extensions
  const extensions = JSON.parse(
    PageConfig.getOption('federated_extensions')
  );

  const queuedFederated = [];

  extensions.forEach(data => {
    if (data.extension) {
      queuedFederated.push(data.name);
      federatedExtensionPromises.push(createModule(data.name, data.extension));
    }
    if (data.mimeExtension) {
      queuedFederated.push(data.name);
      federatedMimeExtensionPromises.push(createModule(data.name, data.mimeExtension));
    }

    if (data.style && !PageConfig.Extension.isDisabled(data.name)) {
      federatedStylePromises.push(createModule(data.name, data.style));
    }
  });

  /**
   * Iterate over active plugins in an extension.
   *
   * #### Notes
   * This also populates the disabled, deferred, and ignored arrays.
   */
  function* activePlugins(extension) {
    // Handle commonjs or es2015 modules
    let exports;
    if (extension.hasOwnProperty('__esModule')) {
      exports = extension.default;
    } else {
      // CommonJS exports.
      exports = extension;
    }

    let plugins = Array.isArray(exports) ? exports : [exports];
    for (let plugin of plugins) {
      if (PageConfig.Extension.isDisabled(plugin.id)) {
        disabled.push(plugin.id);
        continue;
      }
      if (PageConfig.Extension.isDeferred(plugin.id)) {
        deferred.push(plugin.id);
        ignorePlugins.push(plugin.id);
      }
      yield plugin;
    }
  }

  // Handle the registered mime extensions.
  const mimeExtensions = [];
  {{#each jupyterlab_mime_extensions}}
  if (!queuedFederated.includes('{{@key}}')) {
    try {
      let ext = require('{{@key}}{{#if this}}/{{this}}{{/if}}');
      for (let plugin of activePlugins(ext)) {
        mimeExtensions.push(plugin);
      }
    } catch (e) {
      console.error(e);
    }
  }
  {{/each}}

  // Add the federated mime extensions.
  const federatedMimeExtensions = await Promise.allSettled(federatedMimeExtensionPromises);
  federatedMimeExtensions.forEach(p => {
    if (p.status === "fulfilled") {
      for (let plugin of activePlugins(p.value)) {
        mimeExtensions.push(plugin);
      }
    } else {
      console.error(p.reason);
    }
  });

  // Handled the registered standard extensions.
  {{#each jupyterlab_extensions}}
  if (!queuedFederated.includes('{{@key}}')) {
    try {
      let ext = require('{{@key}}{{#if this}}/{{this}}{{/if}}');
      for (let plugin of activePlugins(ext)) {
        register.push(plugin);
      }
    } catch (e) {
      console.error(e);
    }
  }
  {{/each}}

  // Add the federated extensions.
  const federatedExtensions = await Promise.allSettled(federatedExtensionPromises);
  federatedExtensions.forEach(p => {
    if (p.status === "fulfilled") {
      for (let plugin of activePlugins(p.value)) {
        register.push(plugin);
      }
    } else {
      console.error(p.reason);
    }
  });

  // Load all federated component styles and log errors for any that do not
  (await Promise.allSettled(federatedStylePromises)).filter(({status}) => status === "rejected").forEach(({reason}) => {
    console.error(reason);
  });

  const lab = new JupyterLab({
    mimeExtensions,
    disabled: {
      matches: disabled,
      patterns: PageConfig.Extension.disabled
        .map(function (val) { return val.raw; })
    },
    deferred: {
      matches: deferred,
      patterns: PageConfig.Extension.deferred
        .map(function (val) { return val.raw; })
    },
  });
  register.forEach(function(item) { lab.registerPluginModule(item); });
  lab.start({ ignorePlugins });

  // Expose global app instance when in dev mode or when toggled explicitly.
  var exposeAppInBrowser = (PageConfig.getOption('exposeAppInBrowser') || '').toLowerCase() === 'true';
  var devMode = (PageConfig.getOption('devMode') || '').toLowerCase() === 'true';

  if (exposeAppInBrowser || devMode) {
    window.jupyterapp = lab;
  }

  // Handle a browser test.
  if (browserTest.toLowerCase() === 'true') {
    lab.restored
      .then(function() { report(errors); })
      .catch(function(reason) { report([`RestoreError: ${reason.message}`]); });

    // Handle failures to restore after the timeout has elapsed.
    window.setTimeout(function() { report(errors); }, timeout);
  }

}