this在函数中赋值打印有值,在外部失效

'''
beforeCreate() {
plus.device.getOAID({
success: (e)=> {

                this.msaoaid = e.oaid;  
                console.log(this.msaoaid);  
            },  
            fail: function(e) {  
                console.log('getOAID failed: ' + JSON.stringify(e));  
                that.msaoaid = ''  
                console.log(e.oaid);  
            }  
        });  
        console.log('123'+this.msaoaid)  
    },  

'''

外部打印msaoaid无值