refactor(@schematics/angular): use new workspace helpers in polyfill-metadata migration

Author: clydin

packages/schematics/angular/migrations/update-7/polyfill-metadata.ts

@@ -5,13 +5,10 @@
  * 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 { JsonObject, JsonParseMode, JsonValue, parseJson } from '@angular-devkit/core';
-import { Rule, Tree, chain, noop } from '@angular-devkit/schematics';
+import { Rule, Tree, chain } from '@angular-devkit/schematics';
 import * as ts from '../../third_party/github.com/Microsoft/TypeScript/lib/typescript';
-
-function isJsonObject(value: JsonValue): value is JsonObject {
-  return value != null && typeof value === 'object' && !Array.isArray(value);
-}
+import { getWorkspace } from '../../utility/workspace';
+import { Builders } from '../../utility/workspace-models';
 
 /**
  * Remove the Reflect import from a polyfill file.
@@ -29,8 +26,7 @@ function _removeReflectFromPolyfills(tree: Tree, path: string) {
   const recorder = tree.beginUpdate(path);
 
   const sourceFile = ts.createSourceFile(path, source.toString(), ts.ScriptTarget.Latest);
-  const imports = sourceFile.statements
-      .filter(s => s.kind === ts.SyntaxKind.ImportDeclaration) as ts.ImportDeclaration[];
+  const imports = sourceFile.statements.filter(ts.isImportDeclaration);
 
   for (const i of imports) {
     const module = ts.isStringLiteral(i.moduleSpecifier) && i.moduleSpecifier.text;
@@ -45,92 +41,39 @@ function _removeReflectFromPolyfills(tree: Tree, path: string) {
   tree.commitUpdate(recorder);
 }
 
-/**
- * Update a project's target, maybe. Only if it's a builder supported and the options look right.
- * This is a rule factory so we return the new rule (or noop if we don't support doing the change).
- * @param root The root of the project source.
- * @param targetObject The target information.
- * @private
- */
-function _updateProjectTarget(targetObject: JsonObject): Rule {
-  // Make sure we're using the correct builder.
-  if (targetObject.builder !== '@angular-devkit/build-angular:browser'
-      || !isJsonObject(targetObject.options)) {
-    return noop();
-  }
-  const options = targetObject.options;
-  if (typeof options.polyfills != 'string') {
-    return noop();
-  }
-
-  const polyfillsToUpdate = [options.polyfills];
-  const configurations = targetObject.configurations;
-  if (isJsonObject(configurations)) {
-    for (const configName of Object.keys(configurations)) {
-      const config = configurations[configName];
-
-      // Just in case, only do non-AOT configurations.
-      if (isJsonObject(config)
-          && typeof config.polyfills == 'string'
-          && config.aot !== true) {
-        polyfillsToUpdate.push(config.polyfills);
-      }
-    }
-  }
-
-  return chain(
-    polyfillsToUpdate.map(polyfillPath => {
-      return (tree: Tree) => _removeReflectFromPolyfills(tree, polyfillPath);
-    }),
-  );
-}
-
-/**
- * Move the import reflect metadata polyfill from the polyfill file to the dev environment. This is
- * not guaranteed to work, but if it doesn't it will result in no changes made.
- */
 export function polyfillMetadataRule(): Rule {
-  return (tree) => {
-    // Simple. Take the ast of polyfills (if it exists) and find the import metadata. Remove it.
-    const angularConfigContent = tree.read('angular.json') || tree.read('.angular.json');
-    const rules: Rule[] = [];
-
-    if (!angularConfigContent) {
-      // Is this even an angular project?
-      return;
-    }
-
-    const angularJson = parseJson(angularConfigContent.toString(), JsonParseMode.Loose);
+  return async (tree) => {
+    const workspace = await getWorkspace(tree);
 
-    if (!isJsonObject(angularJson) || !isJsonObject(angularJson.projects)) {
-      // If that field isn't there, no use...
-      return;
-    }
-
-    // For all projects, for all targets, read the polyfill field, and read the environment.
-    for (const projectName of Object.keys(angularJson.projects)) {
-      const project = angularJson.projects[projectName];
-      if (!isJsonObject(project)) {
-        continue;
-      }
-      if (typeof project.root != 'string') {
+    const rules: Rule[] = [];
+    for (const [, project] of workspace.projects) {
+      if (typeof project.root !== 'string') {
         continue;
       }
 
-      const targets = project.targets || project.architect;
-      if (!isJsonObject(targets)) {
-        continue;
-      }
+      for (const [, target] of project.targets) {
+        if (target.builder !== Builders.Browser) {
+          continue;
+        }
+
+        const optionPolyfills = target.options?.polyfills;
+        if (optionPolyfills && typeof optionPolyfills === 'string') {
+          rules.push((tree) => _removeReflectFromPolyfills(tree, optionPolyfills));
+        }
+
+        if (!target.configurations) {
+          continue;
+        }
 
-      for (const targetName of Object.keys(targets)) {
-        const target = targets[targetName];
-        if (isJsonObject(target)) {
-          rules.push(_updateProjectTarget(target));
+        for (const configuration of Object.values(target.configurations)) {
+          const configurationPolyfills = configuration?.polyfills;
+          if (configurationPolyfills && typeof configurationPolyfills === 'string') {
+            rules.push((tree) => _removeReflectFromPolyfills(tree, configurationPolyfills));
+          }
         }
       }
     }
 
-    // Remove null or undefined rules.
     return chain(rules);
   };
 }