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ES Modules in Lykn

All Lykn code compiles with sourceType: "module". There is no CommonJS. No require. No module.exports. No .mjs vs .js confusion. Just modules.

What This Means

  • Top-level bind forms are module-scoped, not global. No accidental pollution of globalThis.
  • Top-level await works — modules can await at the top level (Ch 17 covers async in detail).
  • import and export are available — the forms covered in this chapter.
  • Strict mode is implicit — all module code runs in strict mode. No "use strict" needed.

No CommonJS

Before ES modules, Node.js used CommonJS: require() for imports, module.exports for exports. CommonJS modules are synchronous, don’t support tree-shaking, and have different semantics from ESM (value copies vs live bindings).

Lykn skips all of this. If your project needs to consume a CommonJS package, Deno handles the interop transparently. Lykn doesn’t need to.

The reader coming from a Node.js background may miss require. The reader who has debugged a dual-package hazard will not.