Property 'propName' is used before its initialization

[GromovRoman]

Hello everyone!

I am using typescript 4.1.3 and I get this error Property 'propName' is used before its initialization. I can fix it using "!", but I'm not sure how correct it is @inject propName!: propService. Maybe someone can suggest something, thanks.

[kirilldronkin]

There is a few options to deal with it:

1. Use not-null assertion when needed as you described in the subject.
2. Turn off strictPropertyInitialization globally in your tsconfig.json. Turning off the checking globally may be considered as a bad practice, it's quite useful overall.
3. Use declare property modifier introduced in TS 3.7. Note that you have to use it when useDefineForClassFields is enabled (e.g. it's mandatory for MobX's decorators) as I reported in the sibling issue.