# Introduction

## Pragmatic Programmer and Clean Code

### Table of Contents

1. [Setup](#setup-instructions)
2. [Assignments](#assignments)
3. [DRY Assignment](#dry-assignment)
4. [SOLID](#solid)
5. [SOLID Exercises](#exercise-instructions-for-solid)
6. [Law of Demeter](#law-of-demeter)
7. [Exercise for Law of Demeter](#exercise-for-law-of-demeter)
8. [YAGNI](yagni)
9. [KISS](#kiss)
10. [Pragmatic Software Development Tips](#pragmatic-software-development-tips)

This meetup will go over concepts from the books [Pragmatic Programmer](https://pragprog.com/book/tpp/the-pragmatic-programmer) and [Clean Code](https://www.amazon.com/Clean-Code-Handbook-Software-Craftsmanship/dp/0132350882)

## Setup instructions

#### 1. Install node.js via [Node.js](https://nodejs.org/en/download/)

#### 2. Run `npm install` on root level of folder.

#### 3. Run `npm run` to see all the scripts available

## Assignments

Each assignment folder has several exercise files. Read the assignment.md file in order to complete the exercise. Some assignments may or may not have a program.js file that you will test. Each assignment will have a file called program.test.js.

### DRY Assignment

**1. Go to dry folder**

**2. Open assignment.md**

**3. Follow instructions to complete the assignment.**

**4. Run command npm run dry:test**

### SOLID

1. Single Responsibility Principle
   1. a class should have only a single responsibility (i.e. only one potential change in the software's specification should be able to affect the specification of the class).
   2.
      * :scroll: [Single Responsibility Principle](https://github.com/code-craftsmanship-saturdays/pragmatic-programmer-and-clean-code-principles/tree/6c7c043e48f47078daba41160e9e4464978099c4/docs/solid/srp.pdf)
2. Open/Closed Principle
   1. "software entities … should be open for extension, but closed for modification."\\
   2.
      * :scroll: [Open Closed Principle](https://github.com/code-craftsmanship-saturdays/pragmatic-programmer-and-clean-code-principles/tree/6c7c043e48f47078daba41160e9e4464978099c4/docs/solid/ocp.pdf)
3. Liskov Subsitution Principle
   1. "objects in a program should be replaceable with instances of their subtypes without altering the correctness of that program."
   2.
      * :scroll: [Liskov Substitution Principle](https://github.com/code-craftsmanship-saturdays/pragmatic-programmer-and-clean-code-principles/tree/6c7c043e48f47078daba41160e9e4464978099c4/docs/solid/lsp.pdf)
4. Interface Segregation Principle
   1. "many client-specific interfaces are better than one general-purpose interface."
   2.
      * :scroll: [Interface Segregation Principle](https://github.com/code-craftsmanship-saturdays/pragmatic-programmer-and-clean-code-principles/tree/6c7c043e48f47078daba41160e9e4464978099c4/docs/solid/isp.pdf)
5. Dependency Inversion Principle
   1. one should "depend upon abstractions, \[not] concretions."
   2.
      * :scroll: [Dependency Inversion Principle](https://github.com/code-craftsmanship-saturdays/pragmatic-programmer-and-clean-code-principles/tree/6c7c043e48f47078daba41160e9e4464978099c4/docs/solid/dip.pdf)

#### Exercise Instructions for SOLID

1. Go to srp folder with `cd solid/srp`
   1. Run command `npm run solid:srp:test`
   2. Finish exercises by passing the tests.
2. Go to ocp folder with `cd solid/ocp`
   1. Run command `npm run solid:ocp:test:solution`
   2. Mob/Pair program Exercise
3. Go to lsp folder with `cd solid/lsp`
   1. Run command `npm run solid:lsp:test:solution1`
   2. Run command `npm run solid:lsp:test:solution2`
   3. Mob/Pair program Exercise
4. Go to isp folder with `cd solid/isp`
   1. Run command `npm run solid:isp:test`
   2. Mob/Pair program Exercise
5. Go to dip folder with `cd solid/dip`
   1. Run command `npm run solid:dip:test`
   2. Mob/Pair program Exercise

### Law of Demeter

The Law of Demeter (LoD) or principle of least knowledge is a design guideline for developing software, particularly object-oriented programs. In its general form, the LoD is a specific case of loose coupling.

1. Each unit should have only limited knowledge about other units: only units "closely" related to the current unit.
2. Each unit should only talk to its friends; don't talk to strangers.
3. Only talk to your immediate friends.
4. :scroll: [Law of Demeter](https://github.com/code-craftsmanship-saturdays/pragmatic-programmer-and-clean-code-principles/tree/6c7c043e48f47078daba41160e9e4464978099c4/docs/demeter.pdf)

#### Exercise for Law of Demeter

This will be a group exercise where we mob program.

#### KISS

Keep it Simple, Stupid is a simple concept about eliminating complexity.

### Pragmatic Software Development Tips

#### Care About Your Craft

Why spend your life developing software unless you care about doing it well?

#### Provide Options, Don’t Make Lame Excuses

Instead of excuses, provide options. Don’t say it can’t be done; explain what can be done.

#### Be a Catalyst for Change

You can’t force change on people. Instead, show them how the future might be and help them participate in creating it.

#### Make Quality a Requirements Issue

Involve your users in determining the project’s real quality requirements.

#### Critically Analyze What You Read and Hear

Don’t be swayed by vendors, media hype, or dogma. Analyze information in terms of you and your project.

#### DRY—Don’t Repeat Yourself

Every piece of knowledge must have a single, unambiguous, authoritative representation within a system.

#### Eliminate Effects Between Unrelated Things

Design components that are self-contained, independent, and have a single, well-defined purpose.

#### Use Tracer Bullets to Find the Target

Tracer bullets let you home in on your target by trying things and seeing how close they land.

#### Program Close to the Problem Domain

Design and code in your user’s language.

#### Iterate the Schedule with the Code

Use experience you gain as you implement to refine the project time scales.

#### Use the Power of Command Shells

Use the shell when graphical user interfaces don’t cut it.

#### Always Use Source Code Control

Source code control is a time machine for your work—you can go back.

#### Don’t Panic When Debugging

Take a deep breath and THINK! about what could be causing the bug.

#### Don’t Assume It—Prove It

Prove your assumptions in the actual environment—with real data and boundary conditions.

#### Write Code That Writes Code

Code generators increase your productivity and help avoid duplication.

#### Design with Contracts

Use contracts to document and verify that code does no more and no less than it claims to do.

#### Use Assertions to Prevent the Impossible

Assertions validate your assumptions. Use them to protect your code from an uncertain world.

#### Finish What You Start

Where possible, the routine or object that allocates a resource should be responsible for deallocating it.

#### Configure, Don’t Integrate

Implement technology choices for an application as configuration options, not through integration or engineering.

#### Analyze Workflow to Improve Concurrency

Exploit concurrency in your user’s workflow.

#### Always Design for Concurrency

Allow for concurrency, and you’ll design cleaner interfaces with fewer assumptions.

#### Use Blackboards to Coordinate Workflow

Use blackboards to coordinate disparate facts and agents, while maintaining independence and isolation among participants.

#### Estimate the Order of Your Algorithms

Get a feel for how long things are likely to take before you write code.

#### Refactor Early, Refactor Often

Just as you might weed and rearrange a garden, rewrite, rework, and re-architect code when it needs it. Fix the root of the problem.

#### Test Your Software, or Your Users Will

Test ruthlessly. Don’t make your users find bugs for you.

#### Don’t Gather Requirements—Dig for Them

Requirements rarely lie on the surface. They’re buried deep beneath layers of assumptions, misconceptions, and politics.

#### Abstractions Live Longer than Details

Invest in the abstraction, not the implementation. Abstractions can survive the barrage of changes from different implementations and new technologies.

#### Don’t Think Outside the Box—Find the Box

When faced with an impossible problem, identify the real constraints. Ask yourself: “Does it have to be done this way? Does it have to be done at all?”

#### Some Things Are Better Done than Described

Don’t fall into the specification spiral—at some point you need to start coding.

#### Costly Tools Don’t Produce Better Designs

Beware of vendor hype, industry dogma, and the aura of the price tag. Judge tools on their merits.

#### Don’t Use Manual Procedures

A shell script or batch file will execute the same instructions, in the same order, time after time.

#### Coding Ain’t Done ‘Til All the Tests Run

‘Nuff said.

#### Test State Coverage, Not Code Coverage

Identify and test significant program states. Just testing lines of code isn’t enough.

#### English is Just a Programming Language

Write documents as you would write code: honor the DRY principle, use metadata, MVC, automatic generation, and so on.

#### Gently Exceed Your Users’ Expectations

Come to understand your users’ expectations, then deliver just that little bit more.

#### Think! About Your Work

Turn off the autopilot and take control. Constantly critique and appraise your work.

#### Don’t Live with Broken Windows

Fix bad designs, wrong decisions, and poor code when you see them.

#### Remember the Big Picture

Don’t get so engrossed in the details that you forget to check what’s happening around you.

#### Invest Regularly in Your Knowledge Portfolio

Make learning a habit.

#### It’s Both What You Say and the Way You Say It

There’s no point in having great ideas if you don’t communicate them effectively.

#### Make It Easy to Reuse

If it’s easy to reuse, people will. Create an environment that supports reuse.

#### There Are No Final Decisions

No decision is cast in stone. Instead, consider each as being written in the sand at the beach, and plan for change.

#### Prototype to Learn

Prototyping is a learning experience. Its value lies not in the code you produce, but in the lessons you learn.

#### Estimate to Avoid Surprises

Estimate before you start. You’ll spot potential problems up front.

#### Keep Knowledge in Plain Text

Plain text won’t become obsolete. It helps leverage your work and simplifies debugging and testing.

#### Use a Single Editor Well

The editor should be an extension of your hand; make sure your editor is configurable, extensible, and programmable.

#### Fix the Problem, Not the Blame

It doesn’t really matter whether the bug is your fault or someone else’s—it is still your problem, and it still needs to be fixed.

#### “select” Isn’t Broken

It is rare to find a bug in the OS or the compiler, or even a third-party product or library. The bug is most likely in the application.

#### Learn a Text Manipulation Language

You spend a large part of each day working with text. Why not have the computer do some of it for you?

#### You Can’t Write Perfect Software

Software can’t be perfect. Protect your code and users from the inevitable errors.

#### Crash Early

A dead program normally does a lot less damage than a crippled one.

#### Use Exceptions for Exceptional Problems

Exceptions can suffer from all the readability and maintainability problems of classic spaghetti code. Reserve exceptions for exceptional things.

#### Minimize Coupling Between Modules

Avoid coupling by writing “shy” code and applying the Law of Demeter.

#### Put Abstractions in Code, Details in Metadata

Program for the general case, and put the specifics outside the compiled code base.

#### Design Using Services

Design in terms of services—independent, concurrent objects behind well-defined, consistent interfaces.

#### Separate Views from Models

Gain flexibility at low cost by designing your application in terms of models and views.

#### Don’t Program by Coincidence

Rely only on reliable things. Beware of accidental complexity, and don’t confuse a happy coincidence with a purposeful plan.

#### Test Your Estimates

Mathematical analysis of algorithms doesn’t tell you everything. Try timing your code in its target environment.

#### Design to Test

Start thinking about testing before you write a line of code.

#### Don’t Use Wizard Code You Don’t Understand

Wizards can generate reams of code. Make sure you understand all of it before you incorporate it into your project.

#### Work with a User to Think Like a User

It’s the best way to gain insight into how the system will really be used.

#### Use a Project Glossary

Create and maintain a single source of all the specific terms and vocabulary for a project.

#### Start When You’re Ready

You’ve been building experience all your life. Don’t ignore niggling doubts.

#### Don’t Be a Slave to Formal Methods

Don’t blindly adopt any technique without putting it into the context of your development practices and capabilities.

#### Organize Teams Around Functionality

Don’t separate designers from coders, testers from data modelers. Build teams the way you build code.

#### Test Early. Test Often. Test Automatically.

Tests that run with every build are much more effective than test plans that sit on a shelf.

#### Use Saboteurs to Test Your Testing

Introduce bugs on purpose in a separate copy of the source to verify that testing will catch them.

#### Find Bugs Once

Once a human tester finds a bug, it should be the last time a human tester finds that bug. Automatic tests should check for it from then on.

#### Build Documentation In, Don’t Bolt It On

Documentation created separately from code is less likely to be correct and up to date.

#### Sign Your Work

Craftsmen of an earlier age were proud to sign their work. You should be, too.
