refactor(@angular-devkit/schematics): minor cleanup to reduce utility imports

Author: clydin

packages/angular_devkit/schematics/src/tree/host-tree.ts

@@ -10,7 +10,6 @@ import {
   PathFragment,
   PathIsDirectoryException,
   PathIsFileException,
-  clean,
   dirname,
   join,
   normalize,
@@ -369,52 +368,53 @@ export class HostTree implements Tree {
   apply(action: Action, strategy?: MergeStrategy): void {
     throw new SchematicsException('Apply not implemented on host trees.');
   }
+
+  private *generateActions(): Iterable<Action> {
+    for (const record of this._record.records()) {
+      switch (record.kind) {
+        case 'create':
+          yield {
+            id: this._id,
+            parent: 0,
+            kind: 'c',
+            path: record.path,
+            content: Buffer.from(record.content),
+          } as CreateFileAction;
+          break;
+        case 'overwrite':
+          yield {
+            id: this._id,
+            parent: 0,
+            kind: 'o',
+            path: record.path,
+            content: Buffer.from(record.content),
+          } as OverwriteFileAction;
+          break;
+        case 'rename':
+          yield {
+            id: this._id,
+            parent: 0,
+            kind: 'r',
+            path: record.from,
+            to: record.to,
+          } as RenameFileAction;
+          break;
+        case 'delete':
+          yield {
+            id: this._id,
+            parent: 0,
+            kind: 'd',
+            path: record.path,
+          } as DeleteFileAction;
+          break;
+      }
+    }
+  }
+
   get actions(): Action[] {
     // Create a list of all records until we hit our original backend. This is to support branches
     // that diverge from each others.
-    const allRecords = [...this._record.records()];
-
-    return clean(
-      allRecords
-        .map(record => {
-          switch (record.kind) {
-            case 'create':
-              return {
-                id: this._id,
-                parent: 0,
-                kind: 'c',
-                path: record.path,
-                content: Buffer.from(record.content),
-              } as CreateFileAction;
-            case 'overwrite':
-              return {
-                id: this._id,
-                parent: 0,
-                kind: 'o',
-                path: record.path,
-                content: Buffer.from(record.content),
-              } as OverwriteFileAction;
-            case 'rename':
-              return {
-                id: this._id,
-                parent: 0,
-                kind: 'r',
-                path: record.from,
-                to: record.to,
-              } as RenameFileAction;
-            case 'delete':
-              return {
-                id: this._id,
-                parent: 0,
-                kind: 'd',
-                path: record.path,
-              } as DeleteFileAction;
-
-            default:
-              return;
-          }
-        }),
-    );
+    return Array.from(this.generateActions());
   }
 }
 

packages/angular_devkit/schematics/tools/file-system-engine-host-base.ts

@@ -10,7 +10,6 @@ import {
   InvalidJsonCharacterException,
   JsonObject,
   UnexpectedEndOfInputException,
-  isPromise,
   normalize,
   virtualFs,
 } from '@angular-devkit/core';
@@ -21,10 +20,8 @@ import {
   Observable,
   from as observableFrom,
   isObservable,
-  of as observableOf,
   throwError,
 } from 'rxjs';
-import { mergeMap } from 'rxjs/operators';
 import { Url } from 'url';
 import {
   HostCreateTree,
@@ -301,20 +298,17 @@ export abstract class FileSystemEngineHostBase implements FileSystemEngineHost {
     options: OptionT,
     context?: FileSystemSchematicContext,
   ): Observable<ResultT> {
-    // tslint:disable-next-line:no-any https://github.com/ReactiveX/rxjs/issues/3989
-    return ((observableOf(options) as any)
-      .pipe(
-        ...this._transforms.map(tFn => mergeMap((opt: {}) => {
-          const newOptions = tFn(schematic, opt, context);
-          if (isObservable(newOptions)) {
-            return newOptions;
-          } else if (isPromise(newOptions)) {
-            return observableFrom(newOptions);
-          } else {
-            return observableOf(newOptions);
-          }
-        })),
-      )) as {} as Observable<ResultT>;
+    const transform = async () => {
+      let transformedOptions = options;
+      for (const transformer of this._transforms) {
+        const transformerResult = transformer(schematic, transformedOptions, context);
+        transformedOptions = await (isObservable(transformerResult) ? transformerResult.toPromise() : transformerResult);
+      }
+
+      return transformedOptions;
+    };
+
+    return observableFrom(transform()) as unknown as Observable<ResultT>;
   }
 
   transformContext(context: FileSystemSchematicContext): FileSystemSchematicContext {