electron-spell-check-provider

Electron's spell-check API looks straightforward… until you have to pull in and configure node-spellchecker:

webFrame.setSpellCheckProvider('en-US', true, {
spellCheck: function(text) {
+  return !(require('spellchecker').isMisspelled(text));
}
});

Which improperly flags contractions:

And only underlines misspelled words, leaving you to show suggestions yourself…

Or you can use this module:

webFrame.setSpellCheckProvider('en-US', true, new SpellCheckProvider('en-US'));

Installation

npm install electron-spell-check-provider --save

Note: This uses a native module, so you will need to rebuild your modules after installing.

Usage

// In the renderer process:
var webFrame = require('electron').webFrame;
var SpellCheckProvider = require('electron-spell-check-provider');

webFrame.setSpellCheckProvider('en-US', true, new SpellCheckProvider('en-US'));

'en-US' is the only supported language at present.

But how do I show spelling suggestions (in the context menu)?

As the text selection changes, Electron will poll the spell-check provider. If the current word is misspelled, the provider will emit a 'misspelling' event with spelling suggestions:

webFrame.setSpellCheckProvider('en-US', true,
  new SpellCheckProvider('en-US').on('misspelling', function(suggestions) {
    console.log('The text at the site of the cursor is misspelled.',
      'Maybe the user meant to type:', suggestions);
  }
}));

If you save these suggestions, you can then show them in a menu when the 'contextmenu' event next fires.

Here's a full implementation that uses electron-editor-context-menu to build the menu for you in addition to handling some other gotchas:

/**
 * Enables spell-checking and the right-click context menu in text editors.
 * Electron (`webFrame.setSpellCheckProvider`) only underlines misspelled words;
 * we must manage the menu ourselves.
 *
 * Run this in the renderer process.
 */
var remote = require('electron').remote;
var webFrame = require('electron').webFrame;
var SpellCheckProvider = require('electron-spell-check-provider');
// `remote.require` since `Menu` is a main-process module.
var buildEditorContextMenu = remote.require('electron-editor-context-menu');

var selection;
function resetSelection() {
  selection = {
    isMisspelled: false,
    spellingSuggestions: []
  };
}
resetSelection();

// Reset the selection when clicking around, before the spell-checker runs and the context menu shows.
window.addEventListener('mousedown', resetSelection);

// The spell-checker runs when the user clicks on text and before the 'contextmenu' event fires.
// Thus, we may retrieve spell-checking suggestions to put in the menu just before it shows.
webFrame.setSpellCheckProvider(
  'en-US',
  // Not sure what this parameter (`autoCorrectWord`) does: https://github.com/atom/electron/issues/4371
  // The documentation for `webFrame.setSpellCheckProvider` passes `true` so we do too.
  true,
  new SpellCheckProvider('en-US').on('misspelling', function(suggestions) {
    // Prime the context menu with spelling suggestions _if_ the user has selected text. Electron
    // may sometimes re-run the spell-check provider for an outdated selection e.g. if the user
    // right-clicks some misspelled text and then an image.
    if (window.getSelection().toString()) {
      selection.isMisspelled = true;
      // Take the first three suggestions if any.
      selection.spellingSuggestions = suggestions.slice(0, 3);
    }
  }));

window.addEventListener('contextmenu', function(e) {
  // Only show the context menu in text editors.
  if (!e.target.closest('textarea, input, [contenteditable="true"]')) return;

  var menu = buildEditorContextMenu(selection);

  // The 'contextmenu' event is emitted after 'selectionchange' has fired but possibly before the
  // visible selection has changed. Try to wait to show the menu until after that, otherwise the
  // visible selection will update after the menu dismisses and look weird.
  setTimeout(function() {
    menu.popup(remote.getCurrentWindow());
  }, 30);
});

Adding words to the dictionary

You can add a word to the spell-check dictionary by calling the add instance method. Pass the word to add as an argument. Additions to the dictionary are persistent.

let provider = new SpellCheckProvider('en-US');
// ...
let newWord = window.getSelection().toString();
provider.add(newWord);

You can do this in a context menu click handler function for an "Add to Dictionary" menu item.

Contributing

We welcome pull requests! In particular, we'd love to see support for additional languages.

Please lint your code.

Copyright and License

Copyright 2016 Mixmax, Inc., licensed under the MIT License.

Release History

• 1.1.0 Support adding words to the dictionary (#6)
• 1.0.0 Initial release.