Dev How To

Intro

This project is a compilation of my own work mixed with ideas and notes I learn from others. You’ll find pages with tutorial-like explanations on things that interest me and code solutions for book exercises, coding challenges, algorithms and data structures, functional programming stuff, etc.

If you find any problems, or have suggestions, you are welcome to create an issue or a pull request in the Dev How To Gitlab repository.

Licensing Information

The text in this site is licensed under Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) and the code under the General Public License v3.

The source code for this project is located at the Dev How To Gitlab repository.

Table of Contents

• Command Line
  • Intro
  • Single Unix Specification (SUS)
    • Yes, That Website Sucks
  • GNU Coreutils
• Git
  • Indices and tables
• Text Editors
• Haskell
• Ruby
  • Ruby Concepts and Ideas
  • Bits and Bytes of Syntax Suggar
    • Hash Values
    • Map and Hash to Proc to Get Values
    • Hash Transform Values and &:next to_proc
• Ruby on Rails
• PureScript
  • PureScript Resources
  • Useful Libraries
• JavaScript
• TypeScript
  • Tips For Learning TypeScript
    • Union Types
      • never
      • Unions with the empty set ∅
      • Union of some type and any
    • keyof
      • keyof D2 example
      • keyof D3 example index signature
      • keyof with getProp() function
      • keyof in type predicates
      • keyof with mapped types
        • Partial type utility
        • Required type utility
      • References
    • Functions | TypeScript
      • Matching the type
        • A refresher on JavaScript function arguments
    • infer keyword | TypeScript
      • ReturnType
        • Some Details
      • Back to ReturnType
      • Examples Explained
        • FirstArg Type Utility
        • SecondArg Type Utility
        • ArrayItemType Type Utility
      • UnboxObjType, `infer’ in Co-variant Position
• Scheme
  • Building and Installing Chicken Scheme 5.3.0rc3 on macOS Big Sur
    • Downloading and Unpacking the Source
    • Installing GNU Make and GCC
      • Installing GNU Make
      • Installing GNU GCC
    • Trying to Compile
    • Compiling With Appropriate Paths
    • Installing The Built Files
    • TL;DR
• Deno Runtime
  • Project Root Absolute Imports and Import Maps in Deno
    • Intro
    • The Problem
    • The Solution
      • Vim
      • VSCode
• How to Design Programs
  • The Book
  • Design Recipes and Examples
  • Racket and BSL
    • Teaching Languages — htdp/bsl 📖
    • Emacs, Geiser
    • Racket Mode
    • Other libs used in the book
    • DrRacket
    • Naming Source Files
  • Images
  • Other Links
  • Other People’s Notes and Solutions
• Algorithms
  • Big-O of Arrays and Objects
    • Time Complexity
      • Big O of Object Operations
      • Big O of Array Operations
    • Space Complexity
      • Primitive Types
      • Reference Types
    • Code Examples
      • sum() array
        • Unit Tests
        • sum(xs) v1
        • sum(xs) v2
        • sum(xs) v3
      • calcSubtotals(xs)
        • Unit Tests
        • calcSubtotals(xs) v1
  • Space Complexity Examples
    • Sum Array of Numbers
    • Double Array of Numbers
  • Logarithms
  • Problem-Solving
    • Understand The Problem
    • Concrete Examples
      • Frequency Counter Example
    • Break It Down
      • v1
      • v2
    • Solve the problem (or a simplified version of it)
      • charCount() example step by step
        • v1 Simplest Scenario
        • v2 Uppercase and Lowercase
        • v3 Ignore Non-Alphanumeric Chars
        • v4 Refactor Regexp Bit Into Helper Function
  • Helper Functions
    • add(x, y)
    • isEven(n)
  • Split Int Into Even Parts
    • TypeScript
      • Unit Tests
      • v1
      • v2
    • References
• Mostly Adequate Guide to Functional Programming
• Composable Functional JavaScript
  • Intro
  • A Note on Extra Examples and Deviations From The Videos
  • A Note on the Wording Used
    • 01 - Create linear data flow with container style types (Box)
      • Intro
      • The Test Suite
      • A Note on the type 1String
      • Temporary Variables
      • Nested Function Invocations
      • Manual Container
      • Manual Container With Helper Functions
      • Container Type
      • nextChar example
    • 02 - Refactor Imperative to Composed Expression using Box
      • Intro
      • Box
        • The Unit Tests
        • Box Implementation
      • moneyToFloat()
        • The Test Suite
        • Imperative Style
        • Functional Style
      • percentToFloat()
        • The Unit Tests
        • Imperative Style
        • Functional Style
      • applyDiscount()
        • The Unit Tests
        • Imperative Style
        • Functional Style
    • 03 - Enforce a null check with composable code branching using Either
      • Intro to Either, Left and Right
      • Left and Right Unit Tests
      • JSDoc Type Definitions
      • Implementation of Left and Right
      • Use of Left and Right
        • The Problem
        • Actually Making Use of Left and Right
        • Improving With fromNullable
        • Final Thoughts
    • 04 - Use chain for composable error handling with nested Eithers
      • v1 - An Initial, Traditional Implementation
      • v2 - Capture Try Catch With Either
      • v3 - Problems With Invalid, Unparsable JSON
      • v4 - tryCatch JSON.parse
      • v5 Using .chain()
      • v6 Final Implementation
        • getPort Unit Tests
        • getPort Implementation
      • Thoughts
    • 05 - A collection of Either examples compared to imperative code
      • openSite()
        • Unit Tests
        • Helper Functions
        • Imperative Style
        • Functional, Composable Style
      • getPrefs()
        • Unit Tests
        • TypeDefs
        • Imperative Style
        • Functional, Composable Style
      • getStreetName()
        • Unit Tests
        • Imperative Style
        • Functional, Composable Style
      • concatUniq()
        • Unit Tests
        • Imperative Style
        • Functional, Composable Style
      • Final Notes
    • Helper Functions
      • log
      • id (identity)
      • isNil
      • fromNullable
      • Either (Left, Right)
        • Either Unit Tests
        • Either Implementation
      • tryCatch
• Codewars Challenges
  • Chicken Scheme
    • Install Necessary Eggs
    • Running Tests
  • TypeScript
    • Running Tests With Deno
    • Unstable APIs
      • 6kyu
        • Find Int That Appears Odd Number of Times
          • Approach 1 (search and count)
          • Approach 2 Bitwise XOR
          • TypeScript
          • Scheme
        • Which Are In
          • Approach 1
          • JavaScript
          • TypeScript
          • Scheme
        • Friend or Foe
          • Approach 1
          • JavaScript
          • TypeScript
          • Scheme
      • 7kyu
        • Sort Numbers
          • TypeScript
          • v1 Sort Function Callback
• HackerRank Challenges
  • TDD and Developing the Solutions
    • Deno
• Programming
• Databases and SQL
  • Basics
  • Data Definition Language
  • Data Manipulation Language
• Design Patterns
  • Template Method Pattern
    • Use Cases
      • Report Generator
      • Report Generator Ruby Example
      • Email
    • References
  • Strategy Pattern
    • Use Cases
      • Report Generator
        • Ruby
      • Calculating Taxes
    • References
• Character Encoding
• Miscellaneous Tips
  • Paste Image Into Finder
    • The Bash Script
    • Using Quick Actions
    • Add Keyboard Shortcut
    • References