问React Native React - _this2.SetState不是函数

EN

// Subscribers to selected team change
        const subToNewDataChange = subscribe('newData', state => {
            const random = Math.random() * (100 - 15) + 15;
            // Updates the state with the connection change and re renders the view
            this.setState({key:random }, function () {
                this.forceUpdate();
            }.bind(this));
        });