JavaScript Design Patterns: Singleton, Observer, Module and Mediator: Free Course

About this course

Study JavaScript Design Patterns: Singleton, Observer, Module and Mediator through this free English video course from freeCodeCamp. The classroom brings together all 4 public recordings from the selected source curriculum, totaling approximately 16m. You can watch the teaching sequence, search the lesson list and keep track of the recordings you have completed. The course focuses on the subject named in its title. Its value comes from following the explanations and making your own small practice attempts, with enough time to inspect the result and explain the decisions involved.

Course at a glance

What you’ll learn

• Describe the purpose of a singleton
• Explain notification through an observer relationship
• Use a module to organize private and public behaviour
• Describe communication through a mediator
• Compare the four patterns on small examples
• Recognize when a simpler direct structure is sufficient

Skills you’ll gain

• Singleton
• Observer
• Module pattern
• Mediator

Course Overview

Complete finite introduction to the four named patterns; does not claim to cover all software design patterns.

The source lesson list includes “Singleton Design Pattern – Beau teaches JavaScript”, “Module Design Pattern – Beau teaches JavaScript”, “Mediator Design Pattern – Beau teaches JavaScript”. The classroom retains their original titles and positions. Introductions, supplementary explanations and complete-course recordings remain present whenever they are part of the source. A repeated recording is retained at each original position, allowing the course to be checked against the published teaching sequence.

Singleton

Follow the singleton lesson and identify which state or instance the example shares. Explain the reason for centralizing it and the dependency that creates.

Observer

Trace a change through an observer relationship. Identify the subject, subscribers and notification, then describe what happens when a subscriber is added or removed.

Module

Follow the module example and separate the public interface from internal details. Explain how the boundary changes what another part of the program can access.

Mediator

Study the mediator example and compare it with direct communication. Identify the interactions the mediator coordinates and explain when that extra role makes the system easier to understand.

Who is this for?

This course suits learners who want the specific subject described above and who can work at the stated level. It is also useful as a recorded reference when revisiting a concept or comparing a practice attempt with a demonstrated example. Beginners should give the foundational explanations time before moving to more elaborate applications. Experienced learners can use the lesson names to locate a topic, then inspect the surrounding context before applying a technique.

Before you start

JavaScript functions, objects and event-style programming are useful prerequisites. This finite course introduces the four named patterns and does not promise a complete catalogue of all software design patterns.

Put the lessons into practice

Create a fictional reading-list application outline. Use a module for catalogue operations and an observer-style notification for a changed list. Describe where a mediator might coordinate two interface components, then compare it with a direct call. Explain whether a singleton is necessary for the example. Keep each proposed pattern connected to a specific responsibility and avoid adding it only to demonstrate a label.

Treat this suggested exercise as independent practice provided by WikiFree. Keep a short working note containing your inputs, assumptions, result and one point you still need to check. Revisit the relevant recording when a step is unclear, then attempt a small variation without following the demonstration line by line. A result you can explain and reproduce is a more useful study outcome than simply recognizing a familiar term. The exercise is not submitted to an instructor for grading.

Certificate / Assessment

Watching these public recordings and using WikiFree completion tracking does not award a certificate, academic credit, an examination voucher or instructor assessment. The video curriculum is the material included here. Separate platform assignments, credentials and paid services are not part of video viewing. Use the practice output to review which concepts you can explain, which steps you can repeat independently and which questions need another look at the teaching.

Frequently asked questions

Provider: freeCodeCamp. Videos play from the freeCodeCamp channel on YouTube.