KeyboardShortcut class

[hudson-newey]

At the moment we have a KeyboardShortcut interface that we use to store keyboard shortcut information.

This interface allows us to create shortcuts like

const trueShortcut = {
	description: "Add a 'true' decision for 'cow'",
	keys: [shiftSymbol, "q", "o"]
} satisfies KeyboardShortcut;

However, this format is not really useful for keyboard event listeners which would need to listen for the "Q" keys being held down. Notice that "Q" is capitalized in the event listener because it requires shift.

This means that a lot of the time, our event listeners do not use this KeyboardShortcut interface e.g. the ClassificationComponent because it's easier to just use the raw key.

I think that not using the KeyboardShortcut interface is a smell that the interface is not expressive enough.

Therefore, I propose that the KeyboardShortcut interface should handle recognizing its own keyboard events. This would mean that all keyboard shortcut matching would be done in one place and not spread out over the entire client.

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Having a single place for shortcut event matching would also make it easier to change the behavior of shortcuts and add functionality in the future.

E.g. Supporting keyboard patterns would be trivial with a KeyboardShortcut class (example of extending keyboard shortcuts; this is not something that I actually want to support)

const trueShortcut = new KeyboardShortcut({
	description: "make a true decision",
	keys: [[CtrlSymbol, "K"], ["O"]],
});

In this example it would be verbally described as

"Hold ctrl and press 'K', lift up ctrl + 'K', then press 'O' to 'make a true decision'"

An Example of what the class might look like

export class KeyboardShortcut {
    public constructor(public keys: ShortcutKey[], public description?: string, public hasMouse = false)

    // probably not a static field. Maybe a service, but just for illustrative purposes
    private static previousKeys: string[] = [];

    public isShortcut(event: KeyboardEvent) {
        const requiresShift = keys.some((key) => key === shiftSymbol);
        const hasRequiredModifiers = requiredShift && event.shift;

        const previousCombinations = KeyboardShortcut.previousKeys.slice(this.keys.length);
        return previousCombinations.all((key, i) => key === this.keys[i]);
    }
}