alt Hacker NewsUsing keyup makes no sense and is inconsistent with user expectations. For triggering actions (which includes normal typing), you only ever use keydown. (Well, there’s one exception for reasons unclear to me: activating a button by pressing Space. That triggers on keyup like how clicks are on release, while Enter triggers on keydown.) Keyup is limited to things where you’re constantly reacting to the state of a key, as is common in games.
This affects the functionality, too. It is in fact introducing latency by using keyup instead of keydown. Feels bad.
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Key down is used for events that can be duplicated by holding the key. Eg in a text editor, when you want multiples of the same letters, you’d press and hold the key.
Key up is used for when it’s important to only have one occurrence of that event.
Technically you could write code that made key down only react once. But the logical separation makes some sense.
As a user, I’ve not thought too much about this before now. I agree with you mostly, but the keyup on space behaviour actually feels so innate I’d hate any change to it. Keydown on space is “jump”; nothing else.
That’s where the input event is really useful as it allows for more input options than just keyboard and then you don’t have to deal with figuring out if it’s down or up.
On my own computer I can open a context menu and select an action with a single click. Whenever I need to use MS Windows, I always need two and I find that infuriating every time.
For triggering actions (which includes normal typing), you only ever use keydown.
I think you have this wrong, actions generally occur on button release, until that you can move the mouse cursor to a different target, tab to another control, use [ESC] to cancel, and so on. Typing, moving a slider with the cursor keys, and similar things that make use of key repetition while holding down the key are the exception to this.