mayrlabs-language-javascript

JavaScript Code Doctrine

JavaScript must be treated as a strict, production-ready language. We avoid historical JS quirks and default to modern, deterministic, and safe patterns.

The Iron Law

No silent failures, no implicit globals, no parameter mutation.

Core Principles

1. Modern Context (ESM & strict): Always use ES Modules (import/export). Always operate in strict mode (inherent in ESM).
2. Immutability First: Never mutate function parameters. Treat all inputs as read-only. Prefer const over let. Never use var. Use array/object spread operators to create new references instead of mutating existing ones.
3. Pure Functions: Functions should be deterministic. If a function requires external state, inject it as a dependency.
4. Predictable Types (Runtime): Even without TS, ensure objects are structured consistently. Avoid dynamically adding/removing object keys if possible.

Functional & Structural Rules

• Destructuring: Always destructure properties early for clarity.
• Fail Fast: Use Guard Clauses to return early and reduce indentation.
• Async/Await: Promises .then() blocks are banned. Always use async/await encased in explicit try/catch or safe wrapper functions to handle rejections cleanly.
• Iteration: Banish standard for loops unless optimizing a critical raw-performance bottleneck. Use declarative array methods (.map, .filter, .reduce).

Red Flags [BANNED]

• == (Always use ===).
• Modifying prototype of built-in objects.
• Magic numbers/strings without descriptive constant variables.
• Using delete on object properties (use rest destructuring to omit keys instead).