Essential Development Tips for Robust and Maintainable Code

9/20/2016

In the fast-paced world of software development, writing code is often the easiest part. The true challenge lies in writing code that is clean, maintainable, understandable, and resilient—not just for your future self, but for every developer who will ever touch it. This post compiles a collection of essential development tips, principles, and practices that have proven invaluable over years of building and maintaining complex systems.

As one wise developer once put it, "I can’t grasp complex things, period (a bear of very small brain), which is why I need clean code, explicit domain models, and low-fat abstractions." This sentiment underscores the core philosophy behind these tips: simplicity, clarity, and readability should always be paramount.

1. Writing Clean and Understandable Code

The act of reading code far outweighs the act of writing it. Prioritizing readability ensures a smoother development process for everyone involved.

Name Things Well

  • Avoid Verbs for Class Names: Class names should represent nouns (objects or concepts), not actions. For instance, User or Authenticator are good, whereas Enroller or UserAuthenticator (as a class name) can be misleading. A class encapsulates state and behavior related to a noun.
  • Be Explicit, Not Clever: Code that is "clever" might be concise, but it's often obscure and harder to decipher. Always code for the reader, aiming for immediate clarity over stylistic gymnastics.

Organize Your Code

  • Rule of Proximity: Declare variables, methods, and imports as close as possible to where they are used. This reduces cognitive load by keeping related logic together. Standard practices, like grouping imports at the top of a file, are sensible exceptions.
  • Wrap Third-Party Calls: Any interaction with external services or network calls should be encapsulated within dedicated wrapper classes or modules. This centralizes external dependencies, making them easier to manage, test, and swap out if needed. Network calls should never directly sprinkle throughout your application logic.

Minimize Complexity

  • Push Conditionals to the Edges: Design your systems to reduce conditional logic (if/else) in core business logic.
    • For Web Services: Consider creating distinct API endpoints for different scenarios rather than overloading a single endpoint with numerous query parameters that drive conditional branching.
    • For Websites: Explore having separate, specialized pages (even if they share components) instead of one highly conditional page.
    • For Libraries: Offer two distinct functions for different behaviors rather than a single function with a flag. While this might slightly increase the API surface, it often results in clearer intent and simpler usage.
  • Validate Hard at the Edges: Implement strict validation as early as possible (at the system's entry points). This allows you to assume a certain, valid state of data within your application's core logic, thereby reducing the need for redundant conditional checks further down the line. Always provide clear, helpful error messages.

2. Fundamental Principles

These widely recognized principles serve as guiding stars for building robust software. Use them judiciously.

  • You Ain't Gonna Need It (YAGNI): Learn more about YAGNI. Avoid adding functionality until it's actually required. This prevents over-engineering and keeps your codebase lean.
  • The Early Return: Explore early returns. When a function can determine an exit condition early, return immediately. This often simplifies logic by reducing nesting and making the "happy path" clearer.
  • Tell, Don't Ask: Understand Tell, Don't Ask. Instead of asking an object for its data and then performing an operation on that data, tell the object to perform the operation itself. This promotes encapsulation and keeps responsibilities where they belong.
  • Single Responsibility Principle (SRP): Read about SRP. A class or module should have only one reason to change. This principle leads to more modular and maintainable code.
  • Single Source of Truth (SSOT): Discover SSOT. Ensure that every piece of data has a single, unambiguous representation within your system. Avoid duplicating configuration or data definitions across different places.
  • Don't Repeat Yourself (DRY): Explore DRY. Avoid duplicating code or knowledge. However, be wary of over-DRYing. Sometimes, code that looks similar might serve different business purposes. If their underlying reasons diverge, forcing them into a shared abstraction can introduce unnecessary complexity.
    • When to be Cautious with DRY:
      • Code that appears identical but serves distinct business functions.
      • Models with multiple aliases in your system without clear inheritance.
      • Ambiguously named methods; it's better to be vague than incorrectly named, forcing the reader to understand the implementation.
      • Missing abstractions: When two different parts of your system (e.g., NetSuite vs. GP integrations) should share a common interface but don't.

3. Testing Strategies

Effective testing is the bedrock of reliable software.

  • Test from the Outside In: Prioritize end-to-end (e.g., API, UI with Capybara/Cucumber) tests. While more fragile, these tests truly validate the system's overall functionality from a user's perspective. Allow at least some tests to traverse the entire system. Over-reliance on mocks can lead to a false sense of security; aim for integration where it matters.

4. Embracing Standards and Frameworks

Don't reinvent the wheel. Leverage established patterns and tools.

Standards

  • Trust and Use Open Standards: Embrace widely accepted open standards like RFCs, IEEE specifications, and language/framework idioms. This includes adhering to HTTP status codes, appropriate HTTP headers, and conventional casing styles (e.g., underscore_case for Ruby, camelCase for JavaScript, kebab-case for Clojure).
  • Research Standards: Always take the time to understand the standards relevant to your domain.
  • Be Wary of Internal Standards: Question internal standards; they often arise from historical context or specific team preferences. If possible, advocate for making them open or aligning them with existing external standards.

Frameworks

  • Write Less Code: Take pride in deleting code. The less code you have to write (and eventually delete), the better. Frameworks excel at providing common functionalities, saving you immense development time.
  • You're Always Building One: If you choose not to use an existing framework, you will invariably end up building your own, whether intentionally or not. If you desire to build your own, start it as a separate, dedicated project.
  • Leverage Frameworks: Frameworks encapsulate years of collective wisdom and provide robust solutions to common problems. They are designed with thoughtful decisions and compromises.
  • The Learning Curve: Learning a framework is challenging due to the multitude of concepts, opaque design decisions, large surface area of APIs, and the initial overhead of needing only a small piece of its functionality. However, the advantage of not reinventing the wheel far outweighs the disadvantage of not immediately understanding why the wheel is round.

5. Method and Variable Best Practices

Fine-tuning how you structure functions and name variables can dramatically impact code quality.

Methods

  • Size Matters (Initially): When starting, don't prematurely optimize for small methods. Begin with larger methods and extract smaller ones only when a clear, cohesive responsibility emerges. Avoid being overly eager to split methods.
  • Idempotence and Side-Effect Free: Strive to make as many methods as possible idempotent (producing the same result regardless of how many times it's called with the same input) and side-effect free (not modifying state outside their scope). This greatly simplifies reasoning about code.
  • Minimal Information Passing: Pass only the absolutely necessary information into methods. The more data a method accepts, the larger and more brittle its "contract" becomes. If only one field of an object is needed, pass that field explicitly.
  • Consistent Return Types: Except for defined error cases (e.g., raising exceptions), always ensure a method or API returns the same data type or structure. While static languages enforce this, being sensible about it in dynamic languages benefits your future self. Make sure all if/else branches yield consistent return types. If truly disparate return types are needed, consider two separate methods or endpoints.
  • Verbs for Method Names: Method names should always be verbs, clearly indicating the action they perform (e.g., calculateTotal, saveUser, fetchData).

Variables

  • Good Variable Names: Prioritize clarity. Longer, descriptive names are always better than short, ambiguous ones.
  • Avoid Abbreviations: Do not use abbreviations unless they are universally understood within your domain. If you must use them, provide a clear glossary.
  • Reserved Names: Never use generic or context-less variable names like attributes, hash, data, or result. These convey no meaning.
  • Immutable Data (Where Possible): Unless a variable is specifically intended for persistence (e.g., in a database context), avoid changing its value without giving it a new, representative name. This promotes immutable data patterns, making state changes easier to track.

6. Understanding "Cruft"

Cruft is the silent killer of maintainability. Identifying and managing it is crucial.

  • Definition: Cruft refers to code that only makes sense to its original author (and often, only at the moment it was written). When a new developer encounters it, their immediate thought is "What were they thinking?". It lacks a clear, justifiable reason for its current state beyond "it used to be this way."
  • Detection: Sometimes, git history can offer clues, but often cruft exists due to business or engineering decisions that are no longer valid. Engineers are typically better at recognizing technical cruft than business-related cruft.
  • Impact: Cruft adds significant mental overhead, obscuring understanding of business problems or code paths that are no longer in use.

7. Simple Refactor Examples

Small changes can yield big improvements in readability.

Example 1: Boolean Checks

  • Before:
    if (test === true) {
    // ...
}
  • After:
    if (test) {
    // ...
}
    Explanation: If test is already a boolean, directly using it is more concise and idiomatic.

Example 2: Boolean Returns

  • Before:
    if (test) {
    return true;
} else {
    return false;
}
  • After:
    return test; // Or return !!test; for explicit boolean coercion
    Explanation: Directly returning the boolean expression simplifies the logic.

Conclusion

The journey of a software developer is one of continuous learning and refinement. By internalizing these tips—from valuing clean code and strong naming conventions to embracing established principles and leveraging frameworks effectively—you can significantly enhance the quality, maintainability, and longevity of your work. Remember, robust software isn't built overnight; it's a cumulative effort of disciplined practices and a constant pursuit of clarity.