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Typescript keyboard API for consistent cross-browser keybinding, polling input for games, etc.
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MaulingMonkey's typescript keyboard API for consistent cross-browser keybinding, polling input for games, etc.

What? Why?

The vanilla browser keyboard APIs are pretty inconsistent about a lot of things. IE11's keyboardEvent.repeat lies, .code may or may not be available - and if present, has different names for the same keys across different browsers, vanilla numpad events are annoying to differentiate from other hotkeys (e.g. Shift+Numpad1 maps to key: "End"), etc.) which is annoying for roguelikes...

Additionally, doing "the right thing" with the vanilla API isn't straightforward. A lot of webcomics I read implement page handlers for ArrowLeft / ArrowRight, which is nice. Less nice is that most of them don't think to check event.alt or other modifier keys, so their page handlers interfere with browser history navigation (Alt+ArrowLeft, Alt+ArrowRight in Chrome).

Browser Support

OS Browser U.S. Dvorak[1] mmkCode keypress[2]
Windows 7 Chrome 57
Windows 7 IE 11 ✗ [3]
  • [1] Dvorak "support" means mmkKey reports correctly the logical key pressed.
  • [2] Key press events are only partially implemented: mmkCode should be set, if available. mmkKey is not, period.
  • [3] This browser provides no API to get physical key codes - and thus cannot support mmkCode at all.

Basic API

// APIs for consistent results across multiple browsers
keyboardEvent.mmkRepeat // Workaround IE11 keyboardEvent.repeat lying (always being false)
keyboardEvent.mmkKey    // Logical key pressed               (e.g. by keyboard layout labels)
keyboardEvent.mmkCode   // Physical key pressed if available (e.g. ignoring keyboard layout)

// Combination parsing and testing
combo = mmk.keyboard.parseSimpleKeyCombo("Alt+["); // Won't match "[" or "Ctrl+Alt+["
combo = mmk.keyboard.parseSimpleKeyCombo("?Shift+?Ctrl+Alt+["); // Match "Alt+[" or "Ctrl+Alt+[" but not "Meta+["
if (mmk.keyboard.isSimpleKeyCombo(keyboardEvent, combo)) { ... }
conflicts = mmk.keyboard.systemConflictsWithSimpleKeyCombo(combo).filter(conflict => !conflict.overrideable);

Unstablized API Bits

What Why
mmkRepeat Still mulling over how to handle LCtrl + RCtrl "repeats" in Chrome
mmkKey Digits Still mulling over how to handle Digit0 vs Numpad0
mmkCode Numpad Still mulling over how to handle Shift+Numpad 1
mmkCode IE11 Could add fallback for some keys that doesn't rely on keyboard layout (e.g. arrows, basic numpad)
Conflicts API Some conflict detection depends on mmkKey/mmkCode bits above
Key.CtrlLeft Might drop sided keys if we split off a separate 'Code' field.
Key["0"] Ambiguous - Digit0? Include Numpad0? Key based? Code based? ...
Key["."] Punctuation is very likely to be dropped from the Key namespace at some point - too ambiguous
parseSimpleKeyCombo Naming?
isSimpleKeyCombo Naming?
systemConflictsWithSimpleKeyCombo Naming? Bloody wordy.

(Unstable here means the API is subject to change - it shouldn't crash or anything.)

Project Scope

Perhaps easier to say what's not in scope:

  • No "on screen keyboard" support (I should make one, but it can be a separate module)
  • No/limited automatic keyboard layout detection. Even flash doesn't have an API - I'd need to write my own native plugins? Might be able to partially bodge around it.


Via npm

  • Grab NPM via node.js
  • Install per project
    npm i @maulingmonkey/keyboard
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