JavaScript Standards

Prerequisite: Also follow the rules in Dependencies.

Philosophy

Web Native: Prefer web-native solutions and browser-standard APIs where possible.

const over let: If you reach for let, the code can likely be restructured as a transformation.
Pure functions: Prefer functions that take input and return output. Side effects should be explicit and minimal.
Transformation over mutation: Use .map(), .filter(), spread over imperative loops and object mutation.
Object.fromEntries() over .reduce(): When constructing objects from arrays or entries, Object.fromEntries() is cleaner. .reduce() for object construction is acceptable only when fromEntries doesn't fit.
Early returns for guard clauses: Return early at function entry rather than nesting logic in if/else blocks.
iife() for complex const values: When a const value requires conditional logic or early returns to compute, use iife() from @block65/toolkit instead of let + reassignment or raw (() => {})(). This keeps const usage intact while allowing branching logic.

Deprecated APIs: Never use deprecated or legacy APIs (e.g., btoa). Always use modern, standard-compliant alternatives.

Task Runners: Use a dedicated task runner (e.g., moonrepo) if present.
Scripts: If no task runner exists, package.json scripts are acceptable.
Implementation Hygiene: Do not iterate on broken implementations. Identify the root cause and fix it before proceeding.

pnpm Catalogs: If catalog: protocol entries exist in the workspace, use them for versioning.
Centralization: Move any dependency used in multiple packages to the central workspace catalog.
Syntax: Use "dependency-name": "catalog:" in package.json. Never hardcode version strings for dependencies managed by a catalog.