docs: add ModuleWithProviders migration doc (#33085)

PR Close #33085
This commit is contained in:
Kapunahele Wong 2019-10-10 11:44:08 -04:00 committed by Kara Erickson
parent 5632424d04
commit 1b8b04cf26
5 changed files with 96 additions and 0 deletions

2
.github/CODEOWNERS vendored
View File

@ -455,6 +455,7 @@
# ================================================ # ================================================
/packages/compiler-cli/ngcc/** @angular/fw-ngcc @angular/framework-global-approvers /packages/compiler-cli/ngcc/** @angular/fw-ngcc @angular/framework-global-approvers
/aio/content/guide/ngcc.md @angular/fw-ngcc @angular/framework-global-approvers
@ -885,6 +886,7 @@ testing/** @angular/fw-test
/aio/content/guide/migration-dynamic-flag.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes /aio/content/guide/migration-dynamic-flag.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes
/aio/content/guide/migration-injectable.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes /aio/content/guide/migration-injectable.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes
/aio/content/guide/migration-localize.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes /aio/content/guide/migration-localize.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes
/aio/content/guide/migration-module-with-providers.md @angular/fw-docs-packaging @angular/framework-global-approvers @angular/framework-global-approvers-for-docs-only-changes
# ================================================ # ================================================

View File

@ -362,6 +362,10 @@ See the [dedicated migration guide for adding missing `@Injectable` decorators](
See the [dedicated migration guide for `$localize`](guide/migration-localize). See the [dedicated migration guide for `$localize`](guide/migration-localize).
{@a module-with-providers}
### Migrating `ModuleWithProviders`
See the [dedicated migration guide for `ModuleWithProviders`](guide/migration-module-with-providers).
{@a removed} {@a removed}

View File

@ -0,0 +1,78 @@
# `ModuleWithProviders` Migration
## What does this schematic do?
Some Angular libraries, such as `@angular/router` and `@ngrx/store`, implement APIs that return a type called `ModuleWithProviders` (typically via a method named `forRoot()`).
This type represents an `NgModule` along with additional providers.
Angular version 9 deprecates use of `ModuleWithProviders` without an explicitly generic type, where the generic type refers to the type of the `NgModule`.
This schematic will add a generic type to any `ModuleWithProviders` usages that are missing the generic.
In the example below, the type of the `NgModule` is `SomeModule`, so the schematic changes the type to be `ModuleWithProviders<SomeModule>`.
**Before**
```ts
@NgModule({...})
export class MyModule {
static forRoot(config: SomeConfig): ModuleWithProviders {
return {
ngModule: SomeModule,
providers: [
{provide: SomeConfig, useValue: config}
]
};
}
}
```
**After**
```ts
@NgModule({...})
export class MyModule {
static forRoot(config: SomeConfig): ModuleWithProviders<SomeModule> {
return {
ngModule: SomeModule,
providers: [
{provide: SomeConfig, useValue: config }
]
};
}
}
```
In the rare case that the schematic can't determine the type of `ModuleWithProviders`, you may see the schematic print a TODO comment to update the code manually.
## Why is this migration necessary?
`ModuleWithProviders` has had the generic type since Angular version 7, but it has been optional.
This has compiled because the `metadata.json` files contained all the metadata.
With Ivy, `metadata.json` files are no longer required, so the framework cannot assume that one with the necessary types has been provided.
Instead, Ivy relies on the generic type for `ModuleWithProviders` to get the correct type information.
For this reason, Angular version 9 deprecates `ModuleWithProviders` without a generic type.
A future version of Angular will remove the default generic type, making an explicit type required.
## Should I add the generic type when I add new `ModuleWithProviders` types to my application?
Yes, any time your code references the `ModuleWithProviders` type, it should have a generic type that matches the actual `NgModule` that is returned (for example, `ModuleWithProviders<MyModule>`).
## What should I do if the schematic prints a TODO comment?
The schematic will print a TODO comment in the event that it cannot detect the correct generic for the `ModuleWithProviders` type.
In this case, you'll want to manually add the correct generic to `ModuleWithProviders`. It should match the type of whichever `NgModule` is returned in the `ModuleWithProviders` object.
## What does this mean for libraries?
Libraries should add the generic type to any usages of the `ModuleWithProviders` type.
## What about applications using non-migrated libraries?
`ngcc` should transform any non-migrated libraries to generate the proper code.
For more information on `ngcc` see the [ngcc guide](guide/ngcc).

View File

@ -0,0 +1,7 @@
# `ngcc`
## What is `ngcc`?
The Angular Compatibility Compiler, or `ngcc`, is a process that the CLI automatically runs which compiles all your libraries with Ivy.
This means that even if the libraries your app depends on don't use Ivy, `ngcc` will update them to use Ivy for you.

View File

@ -744,6 +744,11 @@
"title": "Usage Analytics", "title": "Usage Analytics",
"tooltip": "For administrators, guide to gathering usage analytics from your users.", "tooltip": "For administrators, guide to gathering usage analytics from your users.",
"url": "cli/usage-analytics-gathering" "url": "cli/usage-analytics-gathering"
},
{
"title": "ngcc",
"tooltip": "Description of the Angular Compatibility Compiler.",
"url": "guide/ngcc"
} }
] ]
}, },