Sign Up

Talk Programming , Career, Mental Health, Talk Personal Finance ❤️‍ Post a query and receive responses ✅

Have an account? Sign In


Have an account? Sign In Now

Sign In

Post a query and receive responses. Ask anything, Ask Mitra ❤️‍

Sign Up Here


Forgot Password?

Don't have account, Sign Up Here

Forgot Password

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.


Have an account? Sign In Now

Sorry, you do not have permission to ask a question, You must login to ask a question.


Forgot Password?

Need An Account, Sign Up Here

Please briefly explain why you feel this question should be reported.

Please briefly explain why you feel this answer should be reported.

Please briefly explain why you feel this user should be reported.

Sign InSign Up

Ask Mitra

Ask Mitra Logo Ask Mitra Logo

Ask Mitra Navigation

  • Home
  • About Us
  • Find Jobs
  • Blogs
    • Add New Blog !
  • Contact Us
Search
Ask A Question

Mobile menu

Close
Ask a Question
  • Ask a Question
  • Home
  • All Categories
  • Find Jobs
  • Points and Swags
    • Badges and Points
    • Ask Mitra Swags
  • Blog
    • Add New Blog !
  • FAQs
  • Community Members 💓
  • About Us
  • Contact Us
Home| Questions|Q 62267
Next
In Process
Aayush Swodari
Aayush SwodariBeginner
Asked: June 26, 20222022-06-26T22:14:52+05:45 2022-06-26T22:14:52+05:45In: —Node Js

Where do the callback is comming from

I followed the mdn docs for learning nodejs. In the code i get confused what is the callback argument passed in funtion and where it is comming from i have not writtern any callback named function

exports.book_detail = function (req, res,next) {
  async.parallel({
    book: function(callback){
      Book.findById(req.params.id).populate(‘author’).populate(‘genre’).exec(callback);
    },
    book_instances: function(callback){
      BookInstance.find({ ‘book’: req.params.id })
      .exec(callback);
    }
  },function(err,results){
    if (err) { return next(err) }
    if (results.book == null){
      let err = new Error(‘Book Not found’);
      err.status =404;
      returnnext(err);
    }
    res.render(‘book_detail’,{title: results.book.title, book:results.book, book_instances: results.book_instances})
  })
};

 

in the code we have book,and book_instance as key and we have function as value with callback as argument

doubtjavascriptquestion
  • 0
  • 1 1 Answer
  • 37 Views
  • 0 Followers
  • 0
Share
  • Facebook

    Related Questions

    • How to join 100day challenge in Data science project
    • Hello guys, ma chai bachelor pass out ho ani I am looking for a place to learn more about flutter. ...
    • How can we build long-term, mutually beneficial relationships with our customers?
    • What does ReactJS intern do in a internship programme?
    • Today I have applied for urgent online e-passport form from Kathmandu and I submitted it but after that I found ...

    You must login to add an answer.


    Forgot Password?

    Need An Account, Sign Up Here

    1 Answer

    • Voted
    • Oldest
    • Recent
    • Random
    1. Abdullah Pundit
      2022-07-06T22:59:38+05:45Added an answer on July 6, 2022 at 10:59 pm

      Please study about ways you can define function.

      Basically there are multiple ways to do it.

       

      1. function name (arguments) { … }
      2. const name = (arguments ) => { … }
      3. const name = function (arguments) { … }

      The 3rd approach is called defining anonymous functions (make function without giving them name but assign to a variable.

      Read more: https://javascript.info/function-expressions

       

      • 0
      • Share
        Share
        • Share on Facebook
        • Share on Twitter
        • Share on LinkedIn
        • Share on WhatsApp

    Sidebar

    Ask A Question

    Your Favourite Topics

    • Announcements
    • Blockchain
    • Books

        • —Non Tech Books
        • —technical books
    • Business and Entrepreneurship
    • Careers
    • College
    • Content and Blog
    • CyberSecurity
    • Design and Arts
    • Devices and Gadgets
    • Digital Marketing
    • Entertainment

        • —Movies-Series-TV
        • —Music
        • —Sports
    • Events
    • For Admins only.
    • Health

        • —Fitness
    • Money

        • —Personal Finance
        • —Stock Market
    • Operating System

        • —linux
        • —windows
    • Other
    • Paid Internship
    • Programming

        • —AI/ML
        • —APIs
        • —C & C#
        • —Django
        • —Flutter
        • —Go
        • —HTML&CSS
        • —Java
        • —JavaScript
        • —Mobile Apps Development
        • —Node Js
        • —NoSQL
        • —Php
        • —Python
        • —React JS
        • —SQL

    Stats

    • Questions 1k
    • Answers 10k
    • Best Answers 391
    • Users 2k

    Top 6 Members This Month

    Vicky

    Vicky

    • 0 Questions
    • 78 Points
    Sensei
    puppet

    puppet

    • 0 Questions
    • 23 Points
    Beginner
    wtfixair

    wtfixair

    • 0 Questions
    • 22 Points
    Beginner
    Dhanmaya

    Dhanmaya

    • 0 Questions
    • 20 Points
    Beginner
    Riyesh

    Riyesh

    • 0 Questions
    • 20 Points
    Beginner
    pranitkarki

    pranitkarki

    • 0 Questions
    • 20 Points
    Beginner

    Trending Tags

    askmitra blockchain c++ career coding College cybersecurity Django Flutter help javascript laptop laravel linux poll Programming python question react web web development wordpress
    • Popular
    • Answers
    • Rounak Agrawal

      Ask Mitra Udemy Courses Giveaway

      • 76 Answers
    • Subedi Bibek

      The Complete JavaScript Course 2022: From Zero to Expert! Udemy ...

      • 73 Answers
    • Subedi Bibek

      Mega Giveaway at askmitra.com 🔥

      • 69 Answers
    • bishwaKiran
      bishwaKiran added an answer Try getting into githubs student program, use your university/collage/school ID… January 30, 2023 at 7:44 pm
    • Sandeep Poudel
      Sandeep Poudel added an answer SOLVED: It was due to unfinished SSL certificate installation January 27, 2023 at 7:11 pm
    • Aashutosh_k
      Aashutosh_k added an answer Software piracy protection system Fingerprint voting system Stock price prediction… January 26, 2023 at 7:37 pm

    Related Questions

    • Any alternate of heroku?

      • 3 Answers
    • Node.js localhost server keeps loading....

      • 2 Answers
    • Does anyone have any idea, how to query in this ...

      • 1 Answer
    • I have encountered this error while deploying my mern project ...

      • 2 Answers
    • Token not sending to the Request Header

      • 0 Answers

    Explore

    • Home
    • Trending Category
      • Programming
      • Web Development
      • —Mobile Apps Development
      • —Stock Market
      • Business and Entrepreneurship
      • Blockchain
      • College
      • —Personal Finance
      • —HTML&CSS
      • —JavaScript
      • —Python
      • —React JS
      • —Node Js
      • —C & C#
      • Content and Blog
      • Careers
    • All Categories
      • Go to All Categories
      • Health
      • —Go
      • —Flutter
      • Digital Marketing
      • —APIs
      • Devices and Gadgets
    • Find Job and Internships
    • Points and Swags
      • Badges and Points
      • Ask Mitra Swags
    • All Blogs
      • Add New Blog !
    • FAQs
    • Community Members 💓
    • Questions
      • Un Answered
      • New Questions
      • Most Seen Questions
      • Most Answered
      • Trending Questions
    • Tags

    Footer

    Ask Mitra

    Ask Mitra

    Ask Mitra is a social question and answer engine that will assist you in forming a community and connecting with others. Talk about programming, your career, your mental health, and your personal finances. ❤️‍ Post a query and receive responses ✅

    Quick Navigation

    • Ask a Question
    • Home
    • All Categories
    • Find Jobs
    • Points and Swags
      • Badges and Points
      • Ask Mitra Swags
    • Blog
      • Add New Blog !
    • FAQs
    • Community Members 💓
    • About Us
    • Contact Us

    Legal Stuff

    • Terms of use and policy