beb8c80787
According to https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/const > Many style guides (including MDN's) recommend using const over let whenever a variable is not reassigned in its scope. This makes the intent clear that a variable's type (or value, in the case of a primitive) can never change.
75 lines
2 KiB
JavaScript
75 lines
2 KiB
JavaScript
class KeyboardHandler {
|
|
constructor() {
|
|
this.queue = [];
|
|
this.shortcuts = {};
|
|
this.triggers = new Set();
|
|
}
|
|
|
|
on(combination, callback) {
|
|
this.shortcuts[combination] = callback;
|
|
this.triggers.add(combination.split(" ")[0]);
|
|
}
|
|
|
|
listen() {
|
|
document.onkeydown = (event) => {
|
|
const key = this.getKey(event);
|
|
if (this.isEventIgnored(event, key) || this.isModifierKeyDown(event)) {
|
|
return;
|
|
}
|
|
|
|
if (key != "Enter") {
|
|
event.preventDefault();
|
|
}
|
|
|
|
this.queue.push(key);
|
|
|
|
for (const combination in this.shortcuts) {
|
|
const keys = combination.split(" ");
|
|
|
|
if (keys.every((value, index) => value === this.queue[index])) {
|
|
this.queue = [];
|
|
this.shortcuts[combination](event);
|
|
return;
|
|
}
|
|
|
|
if (keys.length === 1 && key === keys[0]) {
|
|
this.queue = [];
|
|
this.shortcuts[combination](event);
|
|
return;
|
|
}
|
|
}
|
|
|
|
if (this.queue.length >= 2) {
|
|
this.queue = [];
|
|
}
|
|
};
|
|
}
|
|
|
|
isEventIgnored(event, key) {
|
|
return event.target.tagName === "INPUT" ||
|
|
event.target.tagName === "TEXTAREA" ||
|
|
(this.queue.length < 1 && !this.triggers.has(key));
|
|
}
|
|
|
|
isModifierKeyDown(event) {
|
|
return event.getModifierState("Control") || event.getModifierState("Alt") || event.getModifierState("Meta");
|
|
}
|
|
|
|
getKey(event) {
|
|
const mapping = {
|
|
'Esc': 'Escape',
|
|
'Up': 'ArrowUp',
|
|
'Down': 'ArrowDown',
|
|
'Left': 'ArrowLeft',
|
|
'Right': 'ArrowRight'
|
|
};
|
|
|
|
for (const key in mapping) {
|
|
if (mapping.hasOwnProperty(key) && key === event.key) {
|
|
return mapping[key];
|
|
}
|
|
}
|
|
|
|
return event.key;
|
|
}
|
|
}
|