Module resolution

Resolution maps an import specifier to a file or package entry. Browsers load URLs (or import maps). Node reads `package.json` `exports`, `main`, `module`, extensions, and ESM/CJS mode.

Bundlers add aliases and virtual modules. A path alias in Vite is not understood by Node or Jest until each tool is configured.

`exports` maps can block deep imports into package internals.

On interviews, explain the concept with a concrete example and name the runtime behavior interviewers probe.

Common pitfalls include mixing similar APIs and forgetting edge cases during live coding.

The trade-off is often clarity versus performance or safety versus convenience.

Checklist:

• Identify the runtime resolver.
• Check package exports before deep imports.
• Configure aliases in every tool chain.