Nest: When to use @Inject()?

[bhaidar]

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[ ] Bug report
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When creating services, I simply inject them to a controller as follows:

constructor(private myService: MyService) {}

While reading the section of custom providers it mentions that I should use @Inject() when I want to inject a provider.

I am confused. When to use @Inject() and when it is not needed?
Thanks

[adrien2p]

You can use @Inject when you create a custom provider with a custom token which is not a class that can be interpreted as a type and instanciate. for example when you use a factory if you provide a string based token you can inject it with this decorator.

[bhaidar]

@adrien2p So it's only used when using a string-based token? Other than that, no need to use it when injecting providers?

[adrien2p]

No, it could be a Symbol as well.

But if the injection you want to achieve is base on a class, you don’t need it.

[bhaidar]

What do you mean by Symbol?

[adrien2p]

It’s a primitive datatype
https://www.typescriptlang.org/docs/handbook/symbols.html

[bhaidar]

Oh great! Symbol reminds of InjectionToken.

Thanks @adrien2p a lot! I am paving my way through nestjs still.

[adrien2p]

Basically if the type of what you want to inject is a class then you can avoid to use @Inject, otherwise use it :)

[kamilmysliwiec]

I believe that this issue can be closed then :)

[lock[bot]]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.