When utilizing a 'Token' in the provider() aliasing within Angular 2, the Typescript compiler may display an error message stating 'Unresolved variable or type'. This issue can arise when defining

When working with Typscript, I've encountered an issue where it can't handle a 'Token' in the context of an Angular2 provide() aliasing function. I'm unsure if there's a specific setting in the typescript compiler to address this problem or if I must resort to using a string type alias instead.

For instance, within the main.ts bootstrapping function, the code would look something like:

bootstrap(AppComponent, [ROUTER_PROVIDERS, provide(**alias_token**, Child1aComponent)]);

In my experience, Typescript (specifically in webstorm) shows an error stating 'Unresolved variable or type alias_token.'

While there is an alternative 'provide' function that accepts a string as its first parameter, I am keen on utilizing the Token version if there is a way to do so.

Does anyone have any insights or solutions for this issue?

typescriptangular

Answer №1

**alias_token** must correspond to a valid type (one that actually exists and is imported), or it can be a string, or an OpaqueToken

Here are some examples:

class AliasToken {}

bootstrap(AppComponent, [ROUTER_PROVIDERS, provide(AliasToken, {useClass  Child1aComponent})]);
...
constructor(private alias:AliasToken);

bootstrap(AppComponent, [ROUTER_PROVIDERS, provide('alias_token', {useClass: Child1aComponent})]);
...
constructor(@Inject('alias_token') private alias:AliasToken);

var alias_token = new OpaqueToken("alias");
bootstrap(AppComponent, [ROUTER_PROVIDERS, provide(alias_token, {useClass: Child1aComponent})]);
...
constructor(@Inject(alias_token) private alias:AliasToken);

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