Overview

Miso.Subscription.Keyboard provides global keyboard subscriptions that track which keys are currently held down. All four subscriptions register keydown, keyup, and blur listeners on window; the blur handler clears the pressed-key set so keys cannot get stuck when the window loses focus.

Quick start

import Miso
import Miso.Subscription.Keyboard

-- Fire action with arrow-key state on every key change
subs :: [Sub Action]
subs = [ arrowsSub ArrowsChanged ]

update :: Action -> Effect p props Model Action
update (ArrowsChanged (Arrows x y)) = do
  -- x ∈ {-1, 0, 1}, y ∈ {-1, 0, 1}
  io_ (move x y)

Subscription variants

• keyboardSub — delivers the raw IntSet of all currently pressed keyCodes. Use this when you need to handle arbitrary key combinations.

• arrowsSub — maps the four arrow keys (37–40) to an Arrows value with arrowX ∈ {-1, 0, 1} and arrowY ∈ {-1, 0, 1}.
• wasdSub — same as arrowsSub but for W/A/S/D (keyCodes 87/83/65/68).
• directionSub — fully configurable: supply your own (up, down, left, right) keyCode lists and get the same Arrows mapping.

See also

• Miso.Subscription — re-export hub
• Miso.Event.Types — KeyCode, KeyInfo
• Miso.Html.Event — per-element onKeyDown / onKeyUp