[英]How to change scope back to original function after calling a “local” function within module.exports in Node.JS
我试图在module.exports中的另一个函数“ NextMessageCalculation”中调用另一个本地函数“ MessageScoring”,但是我在使范围变回时遇到了麻烦。 该函数成功调用了另一个本地函数,但是随后更改了作用域,并且先前作用域中的变量现在都返回未定义状态。 我将如何解决此问题,或者有更好的方法来调用本地函数来避免这种情况?
module.exports = {
MessageScoring: function(){
var attrs_list = Object.keys(message_attr_obj);
var score = 0;
for (i in attrs_list){
if(user_data[attrs_list[i]]){
score = score + user_data[attrs_list[i]]["beta"];
}
else{
//user has no response with that attr yet so score is not added
}
}
score = score / attrs_list.length;
return score}... //returns an int
NextMessageCalculation: function(){ //has a call to a mongodb and the logic takes place in the callback
MESSAGE_collection.find({'message_set':user_data.message_set,'id':{$nin:[1111]}}).toArray(function(err,doc){
if (doc.length === 0)
{
USERDATA_collection.update({phone:phone_num},{$set:{send_message:false}},function(err,res) {
db.close()
});
}
else{
var highest_score = "";
var next_message = "";
for (i in doc)
{
console.log(doc[i]['id']);
var score = module.exports.MessageScoring(doc[i].attr_list,user_data);
console.log(doc[i]['id']); <---- becomes undefined here after calling scoring function which correctly returns int
if (highest_score === "")
{
console.log(doc[i]);
next_message = doc[i].id;
highest_score = score;
}
if (highest_score < score)
{
next_message = doc[i].id
highest_score = score;
}
console.log(doc[i].id);
}
使用提升功能,退出modules.expors闭包,并确保MessageScoring不会使数据发生变异。
module.exports = {
MessageScoring,
NextMessageCalculation:
}
function MessageScoring() {
}
function NextMessageCalculation(){
const d = [{ id: 'ok' }];
const i = 0;
console.log(d[i]['id']); //returns ok
var score = MessageScoring(doc[i].attr_list,user_data);
console.log(d[i]['id']); //returns ok
}
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