I am trying to call a controller function from js and use the result for validation purpose.
Unfortunately, the result getting as `undefined` because of the result line is printing before the completion of the ajax call.

here is my code:

***.js**

send: function(e){
e.preventDefault();
var self = this;
var is_submit = self.$target.find('#is_submit').val();
var mobile = self.$target.find('#mobile').val();
var phone = self.$target.find('#phone').val();
var data = self.ajaxcall(mobile,e);
console.log('dddddddd',data);// here it prints undefined.
if (data == false){
return false;
}
this._super(e);

},
})


ajaxcall:function(mobile,e){
var value = {
'flag':'mobile',
'number':mobile
}
ajax.jsonRpc('/checkexisting/','call',value).then(function(data){
console.log('isnide ajax call',data);
return data;
});
},

Here is th console output:

[![enter image description here][1]][1]


[1]: https://i.stack.imgur.com/SK4ib.png

How can i make it as a synchronous mode?