cocos creator 3行飘字 渐隐 tips

cc.Class({
    extends: cc.Component,

    properties: {
        layerBg: cc.Node,
        labelPfb: cc.Prefab,
    },

    // LIFE-CYCLE CALLBACKS:

    onLoad () {
        g_tipsMgr = this
    },

    start () {
        this.rollNoticeList = []
    },

    createShowNode(str) {
        let label = cc.instantiate(this.labelPfb)
        this.layerBg.addChild(label)

        this.rollNoticeList.push(label)
        if (this.rollNoticeList.length > 3) {
            let note = this.rollNoticeList.shift()
            // note.removeFromParent(false)
            note.destroy()
        }

        let rnum = this.rollNoticeList.length
        let spos = cc.v2(0, 0)
        let idx = 1
        for (let i = rnum - 1; i >= 0; --i) {
            let lb = this.rollNoticeList[i]
            if (i == rnum) {
                spos = cc.v2(lb.x, lb.y)
            } else {
                let newy = spos.y + idx * lb.height
                lb.y = newy
                idx = idx + 1
            }
        }

        label.getComponent(cc.Label).string = str
        
        return label
    },

    showRollNotice(str) {
        let label = this.createShowNode(str)

        //时间 秒数
        let holdTime = 5

         // var callback = cc.callFunc(this.onComplete, this);
        let sequence = cc.sequence(cc.fadeTo(holdTime, 0), cc.callFunc(function(target, score) {
            this.rollNoticeList.shift()
            // target.removeFromParent(false)
            target.destroy()
        }, this))//动作完成后删除
        label.runAction(sequence)

    },

    // update (dt) {},
});