The Code Review That Changed Everything

A developer discovered TypeScript enums generate unexpected runtime code after a senior engineer flagged their pull request, revealing that simple enums compile into complex JavaScript functions with reverse mappings nobody uses. Unlike other TypeScript features that disappear during compilation, enums create actual runtime objects that can't be tree-shaken, bloating bundle sizes unnecessarily. The better alternative is using const objects with 'as const', which provides stricter type safety, zero runtime overhead, and cleaner compiled output.