feat(ng-add): add logic for project selection

Since defaultProject is deprecated, the project must be determined differently. Variants:
- Use the defaultProject if given (for compatibility)
- Use the first project if only one is available
- Use the project defined by the --project arg.
- Throw an error.

Author: fmalcher

src/__snapshots__/ng-add.spec.ts.snap

@@ -3,7 +3,6 @@
 exports[`ng-add generating files generates new files if starting from scratch 1`] = `
 "{
   \\"version\\": 1,
-  \\"defaultProject\\": \\"THEPROJECT\\",
   \\"projects\\": {
     \\"THEPROJECT\\": {
       \\"projectType\\": \\"application\\",
@@ -37,7 +36,6 @@ exports[`ng-add generating files generates new files if starting from scratch 1`
 exports[`ng-add generating files overrides existing files 1`] = `
 "{
   \\"version\\": 1,
-  \\"defaultProject\\": \\"THEPROJECT\\",
   \\"projects\\": {
     \\"THEPROJECT\\": {
       \\"projectType\\": \\"application\\",
@@ -70,3 +68,92 @@ exports[`ng-add generating files overrides existing files 1`] = `
   }
 }"
 `;
+
+exports[`ng-add project selection should select the default project when not explicitly given (for compatibility!) 1`] = `
+"{
+  \\"version\\": 1,
+  \\"projects\\": {
+    \\"THEPROJECT\\": {
+      \\"projectType\\": \\"application\\",
+      \\"root\\": \\"PROJECTROOT\\",
+      \\"architect\\": {
+        \\"build\\": {
+          \\"options\\": {
+            \\"outputPath\\": \\"dist/THEPROJECT\\"
+          }
+        },
+        \\"deploy\\": {
+          \\"builder\\": \\"angular-cli-ghpages:deploy\\"
+        }
+      }
+    },
+    \\"OTHERPROJECT\\": {
+      \\"projectType\\": \\"application\\",
+      \\"root\\": \\"PROJECTROOT\\",
+      \\"architect\\": {
+        \\"build\\": {
+          \\"options\\": {
+            \\"outputPath\\": \\"dist/OTHERPROJECT\\"
+          }
+        }
+      }
+    }
+  },
+  \\"defaultProject\\": \\"THEPROJECT\\"
+}"
+`;
+
+exports[`ng-add project selection should select the explicitly defined project 1`] = `
+"{
+  \\"version\\": 1,
+  \\"projects\\": {
+    \\"THEPROJECT\\": {
+      \\"projectType\\": \\"application\\",
+      \\"root\\": \\"PROJECTROOT\\",
+      \\"architect\\": {
+        \\"build\\": {
+          \\"options\\": {
+            \\"outputPath\\": \\"dist/THEPROJECT\\"
+          }
+        }
+      }
+    },
+    \\"OTHERPROJECT\\": {
+      \\"projectType\\": \\"application\\",
+      \\"root\\": \\"PROJECTROOT\\",
+      \\"architect\\": {
+        \\"build\\": {
+          \\"options\\": {
+            \\"outputPath\\": \\"dist/OTHERPROJECT\\"
+          }
+        },
+        \\"deploy\\": {
+          \\"builder\\": \\"angular-cli-ghpages:deploy\\"
+        }
+      }
+    }
+  }
+}"
+`;
+
+exports[`ng-add project selection should select the first project if there is only one 1`] = `
+"{
+  \\"version\\": 1,
+  \\"projects\\": {
+    \\"OTHERPROJECT\\": {
+      \\"projectType\\": \\"application\\",
+      \\"root\\": \\"PROJECTROOT\\",
+      \\"architect\\": {
+        \\"build\\": {
+          \\"options\\": {
+            \\"outputPath\\": \\"dist/OTHERPROJECT\\"
+          }
+        },
+        \\"deploy\\": {
+          \\"builder\\": \\"angular-cli-ghpages:deploy\\"
+        }
+      }
+    }
+  }
+}"
+`;

src/ng-add.spec.ts

@@ -39,19 +39,61 @@ describe('ng-add', () => {
     });
   });
 
+  describe('project selection', () => {
+    it('should select the default project when not explicitly given (for compatibility!)', async () => {
+      const tree = Tree.empty();
+      const angularJSON = generateAngularJson();
+      (angularJSON as any).defaultProject = PROJECT_NAME;
+      tree.create('angular.json', JSON.stringify(angularJSON));
+
+      const resultTree = await ngAdd({
+        project: ''
+      })(tree, {} as SchematicContext);
+
+      const actual = resultTree.read('angular.json')!.toString();
+      expect(prettifyJSON(actual)).toMatchSnapshot();
+    });
+
+    it('should select the explicitly defined project', async () => {
+      const tree = Tree.empty();
+      const angularJSON = generateAngularJson();
+      tree.create('angular.json', JSON.stringify(angularJSON));
+
+      const resultTree = await ngAdd({
+        project: OTHER_PROJECT_NAME
+      })(tree, {} as SchematicContext);
+
+      const actual = resultTree.read('angular.json')!.toString();
+      expect(prettifyJSON(actual)).toMatchSnapshot();
+    });
+
+    it('should select the first project if there is only one', async () => {
+      const tree = Tree.empty();
+      const angularJSON = generateAngularJson();
+      delete (angularJSON as any).projects[PROJECT_NAME]; // delete one project so that one is left
+      tree.create('angular.json', JSON.stringify(angularJSON));
+
+      const resultTree = await ngAdd({
+        project: ''
+      })(tree, {} as SchematicContext);
+
+      const actual = resultTree.read('angular.json')!.toString();
+      expect(prettifyJSON(actual)).toMatchSnapshot();
+    });
+  });
+
   describe('error handling', () => {
-    it('should fail if project not defined', async () => {
+    it('should fail if there are multiple projects in workspace and project is not explicitly defined', async () => {
       const tree = Tree.empty();
       const angularJSON = generateAngularJson();
-      delete angularJSON.defaultProject;
       tree.create('angular.json', JSON.stringify(angularJSON));
 
       await expect(
         ngAdd({
           project: ''
         })(tree, {} as SchematicContext)
       ).rejects.toThrowError(
-        'No Angular project selected and no default project in the workspace'
+        'There is more than one project in your workspace. Please select it manually by using the --project argument.'
       );
     });
 
@@ -134,7 +176,6 @@ function prettifyJSON(json: string) {
 function generateAngularJson() {
   return {
     version: 1,
-    defaultProject: PROJECT_NAME as string | undefined,
     projects: {
       [PROJECT_NAME]: {
         projectType: 'application',

src/ng-add.ts

@@ -18,11 +18,15 @@ export const ngAdd = (options: NgAddOptions) => async (
   const { workspace } = await workspaces.readWorkspace('/', host);
 
   if (!options.project) {
+    // TODO: defaultProject is deprecated as for Angular 14. Remove support here when officially removed from Angular.
     if (workspace.extensions.defaultProject) {
       options.project = workspace.extensions.defaultProject as string;
+    } else if (workspace.projects.size === 1) {
+      // If there is only one project, return that one.
+      options.project = Array.from(workspace.projects.keys())[0];
     } else {
       throw new SchematicsException(
-        'No Angular project selected and no default project in the workspace'
+        'There is more than one project in your workspace. Please select it manually by using the --project argument.'
       );
     }
   }