feat: enable builtin spellchecker

[MarshallOfSound]

This does all the work to get the spellchecker working on all supported platforms. Testing matrix I'm using is outlined below:

• Windows 10
• Windows 8.1
• Windows 7
• Ubuntu 18.04
• Fedora
• RHEL
• macOS 10.14
• macOS 10.15

This is behind a build flag that is now enabled by default. The addition of this introduces a few new APIs.

session.setSpellCheckerLanguages(languageCodes: string[])

This set the required pref that tells the spellchecker which languages it should use, example usage is. session.setSpellCheckLanguages(['en-US', 'fr']) to enable french and american english. This only impacts hunspell based platforms.

session.availableSpellCheckerLanguages: string[] (Readonly)

This is a read only property with an array of supported language codes that you can provide to the set method above.

session.setSpellCheckerDictionaryDownloadURL(url: string)

This is a writeable property that allows you to modify the base URL that Electron will use to download hunspell dictionaries from. By default we will fetch them from the chromium provided CDN, if you don't want your app to do that you can host these yourself and modify this URL here.

For more info on these new APIs check out the new documentation.

Releasing

There is also a new published asset hunspell_dictionaries.zip which is published once (identical across platforms) that includes all the dictionary files and their licenses that you would need to host if you wanted to override the dictionarySourceURL property.

Existing APIs?

Personally I think we should remove the webFrame.setSpellChecker API as this supersedes in every way it but I'm open to other thoughts there. For now I've added a spellcheck option in webPreferences to enable / disable the spellchecker. While we make sure this is gonna work for everyone we can keep both code paths with the intention to deprecate and remove the webFrame method at some point in the future.

Notes: Added support for the built-in spellchecker. We will use the OS spellchecker on macOS and hunspell on all other platforms.

[trop]

@MarshallOfSound has manually backported this PR to "8-x-y", please check out #20897

[astoilkov]

I was very happily surprised to see Electron doing significant improvements to the spellchecker. Congrats on the work!

@MarshallOfSound I have a quick question related to the future of spellchecking in Electron. Do you see a path to deprecating the need for node-spellchecker?

We are building a text editor where we can't use the spellchecking of HTML elements because we need a more advanced implementation. We need methods to manually check if a text is misspelled.

[dziudek]

@MarshallOfSound - is the spellchecker feature working properly at this moment outside macOS? I have experimentally implement it in my electron-based app and it works only on macOS 10.15. On Windows 10 and Ubuntu linux 19.04 there are no visible results of the spellchecking :/

Initially I thought that I have to set language through session.setSpellCheckerLanguages (as it is dedicated to the hunspell platforms), but I have discovered that session.getSpellCheckerLanguages returns ['en-US'] at start, so it shouldn't be a reason.

Also session.availableSpellCheckerLanguages returns 50 items, so the dictionaries seems to be available (and there is a new output directory called "Dictionaries" on Windows 10).

Tested on the newest beta: 8.0.0-beta.6

[vladimiry]

Existing APIs?

Please don't drop existing APIs support.

[dziudek]

@MarshallOfSound - to avoid an impact of the third party reasons (my app is quite complex) - I have created a super simple app based on this tutorial for Windows 10: https://electronjs.org/docs/tutorial/first-app based on Electron 8.0.0-beta.6.

The only difference - I have add to the webPreferences option spellcheck: true

Unfortunately spellchecker is not working :(

[aabuhijleh]

Adding to @dziudek.

I don't know If we're doing something wrong or if the spellchecker is not working properly on Windows.

I left a comment here

Using Windows 10 + Electron 8.0.0-beta.5 inside the simple quick start repo with minimal changes

I'm not getting anything.

+ Additional question

Using session.setSpellCheckerLanguages => we can add a list of supported spellchecker languages.

Does that mean that this spellchecker will automatically detect the language the user is typing?

[MarshallOfSound]

Quick thing folks, commenting on a closed and merged PR is not going to get people to really look at your problem. If you think there's a bug in Electron, raise a new issue with detailed repro steps and it will be triaged appropriately.