Key Binding API

[denehyg]

Adds a Key Binding API that allows plugins to programmatically add and remove key bindings to Reveal's key handling.

• plugins can make use of Reveal's pre-processing logic for key handling so they don't have to replicate (for example, ignoring key presses when paused)
• (optionally) includes key in the help overlay. Unlike Reveal.registerKeyboardShortcut() when key bindings are removed they are also removed from the help overlay
• reduces the need for plugins to directly add keydown event listeners that can't be overridden by user defined bindings using keyboard config option
• incorporates API usage into notes plugin (should fix Keyboard binding "s" does not override Speaker Notes #1832 and Keyboard Bindings Trigger when using electron <webview> tag #1630)
• passes keydown event to config.keyboardCondition() to allow plugins to filter keyboard based on keycodes. Use case: the reveal.js-menu plugin blocks Reveal keyboard interaction (using keyboardCondition) when the menu is open but using the key binding API to toggle the menu fails to close the menu unless the 'm' key is allowed to pass through to Reveal.

[denehyg]

This will also provide access for plugins to respond to Reveal.triggerKey(), which is currently not possible as triggerKey() directly invokes onDocumentKeyDown() without generating key press. For example, Reveal.triggerKey(83) should open the notes window, but is ignored.

[hakimel]

This is a great addition. Thanks for a well structured PR with docs, comments and all 🙌

[denehyg]

You’re welcome, glad it was useful.