HTML5 2D平台游戏开发——角色动作篇之指令技

class Instruct {
    constructor(callback) {
        this.instructs = {};    
        this.MAX_INTERVAL = 250;    //超时时间
        this.interval = 0;    //上一次输入的时间
        this.pressedKeys = [];    //记录输入
        this.callback = callback;

        window.addEventListener(‘keydown‘,this.onKeyDown.bind(this));
    }

    //注册指令
    registerinstruct(instructName,instructKeys) {
        if(this.instructs[instructName]) return false;
        this.instructs[instructName] = instructKeys;
        return true;
    }
    onKeyDown(e) {
        let now = +new Date;
        if(now - this.interval > this.MAX_INTERVAL) this.pressedKeys = [];
        this.interval = now;
        //记录指令
        this.pressedKeys.push(e.keyCode);
        //检查指令
        this.checkForinstruct();
    }

    checkForinstruct() {
        let instructFound = ‘‘;

        for(let instructName in this.instructs) {
            if(this.instructs.hasOwnProperty(instructName)) {
                //通过比对已记录的指令与设置好的指令来确认是否符合条件
                if (this.pressedKeys.join(‘ ‘).indexOf(this.instructs[instructName].join(‘ ‘)) > -1) {
                    instructFound = instructName;
                    break;
                }
            }
        }
        if(instructFound !== ‘‘) {
            this.pressedKeys = [];
            this.callback && this.callback.call(this,instructFound);
        }
    }

    removeinstruct(instructName) {
        if(this.instructs[instructName]) {
            this.instructs[instructName] = undefined;
            return true;
        }
        return false;
    }
}

var instruct = new Instruct((matching) => {
    console.log(matching);
});

instruct.registerinstruct(‘demo‘,[83,68,83,65,74]);  // ↓ → ↓ ← J