angular-cn/packages/compiler-cli/linker/src/linker_import_generator.ts
Pete Bacon Darwin 7e742aea7c refactor(compiler-cli): linker - add Babel plugin, FileLinker and initial PartialLinkers (#39116)
This commit adds the basic building blocks for linking partial declarations.
In particular it provides a generic `FileLinker` class that delegates to
a set of (not yet implemented) `PartialLinker` classes.

The Babel plugin makes use of this `FileLinker` providing concrete classes
for `AstHost` and `AstFactory` that work with Babel AST. It can be created
with the following code:

```ts
const plugin = createEs2015LinkerPlugin({ /* options */ });
```

PR Close #39116
2020-10-19 11:23:45 -07:00

39 lines
1.4 KiB
TypeScript

/**
* @license
* Copyright Google LLC All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {ImportGenerator, NamedImport} from '../../src/ngtsc/translator';
import {FatalLinkerError} from './fatal_linker_error';
/**
* A class that is used to generate imports when translating from Angular Output AST to an AST to
* render, such as Babel.
*
* Note that, in the linker, there can only be imports from `@angular/core` and that these imports
* must be achieved by property access on an `ng` namespace identifer, which is passed in via the
* constructor.
*/
export class LinkerImportGenerator<TExpression> implements ImportGenerator<TExpression> {
constructor(private ngImport: TExpression) {}
generateNamespaceImport(moduleName: string): TExpression {
this.assertModuleName(moduleName);
return this.ngImport;
}
generateNamedImport(moduleName: string, originalSymbol: string): NamedImport<TExpression> {
this.assertModuleName(moduleName);
return {moduleImport: this.ngImport, symbol: originalSymbol};
}
private assertModuleName(moduleName: string): void {
if (moduleName !== '@angular/core') {
throw new FatalLinkerError(
this.ngImport, `Unable to import from anything other than '@angular/core'`);
}
}
}