下面为什么不执行？

let interval = setInterval(()=>{
        let {orderTime, staticTime} = this.state;
        let nowTime = Date.now();
        let sub = Math.floor((orderTime + staticTime - nowTime)/1000);
        console.log('sub',sub);
        if(sub<=0){
            clearInterval(interval);
            this.setState({
                tip:'支付超时',
                isFalse:true
            });
            return;
        }
        let minutes = parseInt(sub/60);
        let Seconds = sub%60;
        let tip = '订单已提交，请在'+minutes+'分'+Seconds+'秒内完成支付';
        console.log(tip);
        this.setState({
            tip:tip,
            isFalse:false
        });
    },1000);