carrot/assets/Script/MainScene.ts

import { _decorator, Component, director, instantiate, Node, Prefab,  UITransform, Vec3 } from 'cc';
import { GameData } from './GameData';
const { ccclass, property } = _decorator;

@ccclass('MainScene')
export class MainScene extends Component {
    @property(Prefab)
    countDown:Prefab;
    
    speed:number = 0;
    boss:Node = null;
    countDownTS:any = null;

    protected onLoad(){
        //let gameData = instantiate(GameData);
        this.speed = GameData.speed;
    }

    start() {
        let countDown = instantiate(this.countDown);
        this.node.addChild(countDown);
        //获取倒计时预制体脚本
        this.countDownTS = countDown.getComponent("CountDown");

        this.boss = this.node.getChildByName("boss_05_normal");
    }

    update(deltaTime: number) {
        //倒计时结束，游戏开始
        if(this.countDownTS.isOver){
            let x =this.boss.getPosition().x;
            x += this.speed * deltaTime;
       
            if(x >= (this.node.getComponent(UITransform).contentSize.width)/2){
                this.speed = 0;
            }else{
                this.boss.setPosition(new Vec3(x,this.boss.getPosition().y));
            }
        }
    }
}