Effective Dependency Management in TypeScript: A Key to Maintainable Codebases

The Challenges of Unchecked Dependencies

When left unchecked, dependencies can lead to a range of issues, including:

• Tight Coupling: Modules become overly dependent on each other, making it difficult to modify or replace individual components without affecting the entire system.
• Security Risks: Outdated or vulnerable dependencies can expose your application to security threats.
• Performance Issues: Excessive dependencies can result in bloated bundle sizes, slowing down your application.

Introducing Good Fences

To overcome these challenges, we’ll use Good Fences, a TypeScript package that enables you to create and enforce boundaries between modules. By defining explicit dependencies and rules, you can ensure that your codebase remains modular, maintainable, and scalable.

A Practical Example

Let’s consider a simple React application that calculates the nth number of the Fibonacci or Pell series. We’ll create three fenced directories: math, store, and ui. Each directory will have its own set of rules and dependencies, ensuring that the implementation details remain private and the dependencies are explicit.

mkdir math store ui

Configuring Good Fences

To configure Good Fences, we’ll create a fence.json file in each directory, defining the rules and dependencies for that module. For example, the math directory might have a rule that only allows imports from the index.ts file:

{
  "rules": [
    {
      "type": "import",
      "from": "index.ts"
    }
  ]
}

The ui directory might have a rule that prevents imports from the logic directory:

{
  "rules": [
    {
      "type": "import",
      "notFrom": "logic"
    }
  ]
}

Automating Dependency Checks

With Good Fences, you can automate dependency checks by running the good-fences command in your terminal:

npx good-fences

This will ensure that your codebase adheres to the defined rules and dependencies, preventing issues like tight coupling and security risks.