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Bob Watson
a6d953e145
This commit prepares the documentation directories for future tutorials organized by directory. Also, it moves the Angular Libraries topic from the Tutorials section to Developer Guides in TOC PR Close #48162
31 lines
1.2 KiB
Markdown
31 lines
1.2 KiB
Markdown
@name No Provider Found
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@category runtime
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@videoUrl https://www.youtube.com/embed/lAlOryf1-WU
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@shortDescription No provider for {token} found!
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@description
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You see this error when you try to inject a service but have not declared a corresponding provider. A provider is a mapping that supplies a value that you can inject into the constructor of a class in your application.
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Read more on providers in our [Dependency Injection guide](guide/dependency-injection).
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@debugging
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Work backwards from the object where the error states that a [provider](guide/architecture-services) is missing: `No provider for ${this}!`. This is commonly thrown in [services](tutorial/tour-of-heroes/toh-pt4), which require non-existing providers.
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To fix the error ensure that your service is registered in the list of providers of an `NgModule` or has the `@Injectable` decorator with a `providedIn` property at top.
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The most common solution is to add a provider in `@Injectable` using `providedIn`:
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<code-example format="typescript" language="typescript">
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@Injectable({ providedIn: 'app' })
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</code-example>
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<!-- links -->
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<!-- external links -->
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<!-- end links -->
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@reviewed 2022-02-28
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