feat(language-service): allow code refactorings to compute edits asyn…

…chronously (#57214)

VSCode explicitly split code actions into two stages:

 - what actions are active?
 - what are the edits, if the user presses the button.

The latter stage may take longer to compute complex edits, perform
analysis. This stage is currently implemented via our non-LSP standard
`applyRefactoring` method. We should make it asynchronous, so that it
can easily integrate with migrations that aren't synchronous/or compute
in parallel.

Long-term we may want to revisit this given integration in 1P with the
language service as an actual TS server plugin; but it's not necessary
right now and we shouldn't block the effort on this for now.

PR Close #57214

packages/language-service/api.ts

@@ -91,7 +91,7 @@ export interface NgLanguageService extends ts.LanguageService {
     positionOrRange: number | ts.TextRange,
     refactorName: string,
     reportProgress: ApplyRefactoringProgressFn,
-  ): ts.RefactorEditInfo | undefined;
+  ): Promise<ts.RefactorEditInfo | undefined>;
 
   hasCodeFixesForErrorCode(errorCode: number): boolean;
 }

packages/language-service/src/language_service.ts

@@ -549,12 +549,26 @@ export class LanguageService {
     );
   }
 
-  applyRefactoring(
+  /**
+   * Computes edits for applying the specified refactoring.
+   *
+   * VSCode explicitly split code actions into two stages:
+   *
+   *  - 1) what actions are active?
+   *  - 2) what are the edits? <- if the user presses the button
+   *
+   * The latter stage may take longer to compute complex edits, perform
+   * analysis. This stage is currently implemented via our non-LSP standard
+   * `applyRefactoring` method. We implemented it in a way to support asynchronous
+   * computation, so that it can easily integrate with migrations that aren't
+   * synchronous/or compute edits in parallel.
+   */
+  async applyRefactoring(
     fileName: string,
     positionOrRange: number | ts.TextRange,
     refactorName: string,
     reportProgress: ApplyRefactoringProgressFn,
-  ): ts.RefactorEditInfo | undefined {
+  ): Promise<ts.RefactorEditInfo | undefined> {
     const matchingRefactoring = allRefactorings.find((r) => r.id === refactorName);
     if (matchingRefactoring === undefined) {
       return undefined;

packages/language-service/src/refactorings/refactoring.ts

@@ -40,7 +40,7 @@ export interface Refactoring {
     fileName: string,
     positionOrRange: number | ts.TextRange,
     reportProgress: ApplyRefactoringProgressFn,
-  ): ts.RefactorEditInfo;
+  ): Promise<ts.RefactorEditInfo>;
 }
 
 export const allRefactorings: Refactoring[] = [];

packages/language-service/src/ts_plugin.ts

@@ -281,7 +281,7 @@ export function create(info: ts.server.PluginCreateInfo): NgLanguageService {
     positionOrRange: number | ts.TextRange,
     refactorName: string,
     reportProgress: ApplyRefactoringProgressFn,
-  ): ts.RefactorEditInfo | undefined {
+  ): Promise<ts.RefactorEditInfo | undefined> {
     return ngLS.applyRefactoring(fileName, positionOrRange, refactorName, reportProgress);
   }