Proper Keyboard

constants.ts

export const KEY_TAB = 9;
export const KEY_SHIFT = 16;
export const KEY_CONTROL = 17;
export const KEY_ALT = 18;
export const KEY_SPACE = 32;
export const KEY_LEFT = 37;
export const KEY_UP = 38;
export const KEY_RIGHT = 39;
export const KEY_DOWN = 40;
export const KEY_E = 69;
export const KEY_W = 87;
export const KEY_A = 65;
export const KEY_D = 68;
export const KEY_Q = 81;
export const KEY_S = 83;

index.ts

// False -> Up, True -> Down
const pressedKeys: { [key:number]: boolean } = {};

const mappedKeys: { [from: number]: /*to*/ number} = {};

document.addEventListener("keydown", (e: KeyboardEvent)=>{
  let keyCode = mappedKeys[e.keyCode] || e.keyCode;
  if(pressedKeys[keyCode] !== undefined) {
    e.preventDefault();
    pressedKeys[keyCode] = true;
  }
});

document.addEventListener("keyup", (e: KeyboardEvent) => {
  let keyCode = mappedKeys[e.keyCode] || e.keyCode;
  if (pressedKeys[keyCode] !== undefined) {
    e.preventDefault();
    pressedKeys[keyCode] = false;
  }
});


export function register(...keys: number[]) {
  for (let key of keys) {
    pressedKeys[key] = false;
  }
}

export function deregister(...keys: number[]) {
  for(let key of keys) {
    delete pressedKeys[key];
  }
}

export function map(from: number, to: number) {
  mappedKeys[from] = to;
}

export function unmap(from: number) {
  delete mappedKeys[from];
}

export function isDown(key: number): boolean {
  return pressedKeys[key] || false;
}