How to import reflect-metadata correctly

Question

So I have a TypeScript project I am working on and I want to make use of the reflect-metadata package. I am a little confused about the correct way of importing this. It was my understanding that this only needed to be imported once in your "main" file. So in my case I have an app.ts in which I import reflect-metadata as the very first thing:

import 'reflect-metadata';

import ReflectionClass from '@src/Reflection/ReflectionClass';
...

ReflectionClass then in turn imports another class that eventually calls Reflect.getMetadata(). However, this fails with error

error TS2339: Property 'getMetadata' does not exist on type 'typeof Reflect'.

Only when I import reflect-metadata explicitly in the relevant file does the error disappear. Is this the correct way to do this? In other words, do I need to import reflect-metadata in each file that uses it as opposed to a global, one time import in your main file?

Answer 1

To answer my own question; yes, you only have to import it once. I did some overall project re-arrangement which among others involved replacing ts-node for a rollup based solution and removing a bunch of unused packages. After that a single import of reflect-metada now does work. Unfortunately I cannot deduce the exact cause of my original problem, only that it is solved now after reorganisation. Perhaps some other package was interfering with it.

Answer 2

Yes, this is because there is no export in the package of reflect-metadata.