smartgame/js/traits/KeyboardControls.js

import {Trait} from '../Entity';

export default class KeyboardControls extends Trait {
	constructor(entity) {
		super(entity, "keyboardControls");

		this.speed = 500;
		this.map = {
			KeyA: 'left',
			KeyD: 'right',
		};

		this.pressed = {};
	}

	onkey(evt) {
		let name = this.map[evt.code];
		if (name == null) return;
		evt.preventDefault();
		this.pressed[name] = evt.type === 'keydown';
	}

	init() {
		window.addEventListener("keydown", e => this.onkey(e));
		window.addEventListener("keyup", e => this.onkey(e));
	}

	update(dt) {
		if (this.pressed.left)
			this.entity.velocity.x -= this.speed * dt;
		if (this.pressed.right)
			this.entity.velocity.x += this.speed * dt;
	}
}