我想在节点中的另一个函数中访问值，但我得到结果未定义？

Question

如何在任何变量旁边加速？

if

Answer 1

var rates = require('./rate.js');

rates.fromBTC(1, currency, function (response) {     
        console.log(response) //you will get rate here
})

//in rate.js file
exports.fromBTC = function(num,currency,callback){
  /*
  do some operation to find rate
  */
  return callback
}