Firefox does not fire `beforeinput` events

Firefox does not currently support the beforeinput event, which Slate uses under the covers to be notified whenever the user triggers an input into the editor (inserts, deletes, cuts, pastes, drops, etc.). These beforeinput events are cancellable and we use them to then do the Slate-equivalent of whatever the event was.

Right now we hack around this for Firefox and handle some of the common input cases. However, there’s only so much we can do. And input events like formatBold, or insertFromComposition are hard to polyfill. (There might be ways to improve our existing ones, if you see them please PR!)

This is also the reason we disable autoCorrect and spellCheck in Firefox on the contenteditable element, since we have no easy way of determining when those changes occur.

Here are the bug reports… (please vote for and follow them!)

• https://bugzilla.mozilla.org/show_bug.cgi?id=970802
• https://bugzilla.mozilla.org/show_bug.cgi?id=1305387
• https://bugzilla.mozilla.org/show_bug.cgi?id=1449831

Once these are supported Firefox will get improved editing support (autocorrect, spellcheck, IME composition, B/U/I toolbars, etc.). And we’ll be able to reduce bundle size for everyone by removing the current Firefox-specific hacks.

[rescribet]

https://bugzilla.mozilla.org/show_bug.cgi?id=970802 and https://bugzilla.mozilla.org/show_bug.cgi?id=1449831 have been marked as fixed 👍

[ClubicTech]

+1 I force “true” here https://github.com/ianstormtaylor/slate/blob/f4ee75d13d219214fd12c1b10448098f4c070b77/packages/slate-react/src/components/editable.tsx#L41 and spellcheck work perfectily on firefox 76.