javascript-patternslisted

# JavaScript patterns Default assumption: a project running on the current Node.js Active LTS (Node 24, "Krypton") or a modern browser baseline. - If the project also uses TypeScript, the type-aware skill applies on top of these language patterns. - Adapt advice to the Node version in the project's `.nvmrc`, `.tool-versions`, or `engines` field in `package.json`. ## Reference files | File | Covers | | ---------------------------------------------------------------------- | -------------------------------------------------------------------------------- | | [reference/modules.md](reference/modules.md) | ESM and CJS, `package.json` `"type"`, dynamic `import()`, dual-package hazard | | [reference/syntax.md](reference/syntax.md) | Modern syntax: optional chaining, nullish coalescing, logical assignment, `at()` | | [reference/async.md](reference/async.md) | `async`/`await`, `Promise.*`, `for await...of`, top-level `await` | | [reference/errors.md](reference/errors.md) | Error subclasses, `Error.cause`, unhandled rejection, `using` (advisory) | | [reference/equality-and-numbers.md](reference/equality-and-numbers.md) | `===`, `Number.isNaN`, `Array.isArray`, IEEE 754, `BigInt` | | [re