Question

我是NodeJs中的新手我正试图从Node Js中的另一个函数获得响应。我在Nodejs中调用slug函数。我必须在插入之前获得slug但总是在做出回应undefined 我用的是noejs package slugs

var slugs = require("slugs");

我在打电话 genslug(user.name)就像这样。

genslug(connection,slugs(user.name),1,slugs(user.name),callback)

像这样创建了一个函数genslug

var genslug = function(connection,slug,counter=1,orgSlug,callback) {
    var query = connection.query('SELECT * FROM users WHERE slug = ?',slug,function(err,res) {
        if(err)
            callback({status: 'error', error : err});
        if(res.length > 0){
            counter++;
            slug = orgSlug+'-'+counter;
            genslug(connection,slug,counter,orgSlug,callback);
        }else{
            callback(false, slug);
        }
    });
}

但总是得到undefined。请回复如果有人知道这个

Answer 1

Understand the callback nature.

First argument always takes as error and second takes as success.

In your case it always execute in error block from were you are calling the function since you are passing else in final callback.

Try to remove false from final callback

var genslug = function(connection,slug,counter=1,orgSlug,callback) {
    var query = connection.query('SELECT * FROM users WHERE slug = ?',slug,function(err,res) {
        if(err)
            callback({status: 'error', error : err});
        if(res.length > 0){
            counter++;
            slug = orgSlug+'-'+counter;
            genslug(connection,slug,counter,orgSlug);
        }else{
            callback(null, slug);
        }
    });
}

如何从外部函数NodeJ返回响应

2 个答案: