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reflect-metadata specific version needed?

See original GitHub issue

I’m submitting a request

Current behavior

NestJs currently seems to depend on a specific version of reflect-metadata (0.1.10) and will complain in NPM unless you resolve this SPECIFIC version, I tried higher versions and it complained it needed that specific one.

Expected behavior

It should ideally not need any specific polyfill for Reflect.getMetadata etc it should just expect the consumer to provide one (until nodejs etc) doesn’t need it polyfilled.

Currently to my knowledge there are 2 available polyfills:

core-js
reflect-metadata

Problem here is if you were to have both of them in a project your metadata gets wiped as each polyfill is replacing each others polyfill (this may be fixed now but was an issue a few months back).

Minimal reproduction of the problem with instructions

Make a new project
Add restjs dependencies
See error for missing reflect-metadata 0.1.10
install 0.1.12 version of reflect-metadata
See error for missing reflect-metadata 0.1.10

What is the motivation / use case for changing the behavior?

It just seemed odd that it should force you to use a specific version of a polyfill, and in some cases people may want to use core-js which would probably cause decorators that use metadata to blow up.

Recommended solution?

I would remove the dependency on reflect-metadata entirely, and just include a devDependency for @types/reflect-metadata, that will allow you to write TS code that uses metadata, then you require the consumer to provide a relevant polyfill (as listed above).

This is done on one of my other libs: