[plugin-terser] The worker approach to running Terser breaks many valid Terser options

[justinfagnani]

• Rollup Plugin Name: plugin-terser
• Rollup Plugin Version: 0.4.4
• Rollup Version: 4.24.0
• Operating System (or Browser): Linux
• Node Version: v18.20.3
• Link to reproduction (⚠️ read below): https://stackblitz.com/edit/rollup-repro-qx7xkl?file=package.json

Expected Behavior

All valid Terser options are supported. For this reproduction, the Terser nth_identifier option works.

Actual Behavior

An exception during build because only some of the code for the nth_identifier option is serialized. Other things seem to break from serializing the options, like nameCache updates.

Additional Information

The offending line that shows up in stack traces is here:

plugins/packages/terser/src/worker.ts

Line 39 in 4a2358a

const options = eval2(`(${data.options})`);

But, the technique of taking options in one realm and serializing them to another, like a worker, is just not generally workable. Not all Terser options will be serializable. Functions are an obvious case, but I've had other cases of objects with prototypes, etc., breaking too.