feat(extensions): Allow generation of help content for extension commands

Each CLI extension may add new commands to CLI. Allow showing command help for these commands in case:
1. Commmand execution fails.
2. Users need more information for command - `tns <command> --help`
3. Users need full html help for command - `tns help <command>`.

Each extension that wants to use this functionality will have to add `nativescript` key in its `package.json` and add `docs` key in it. The `docs` key must point to the directory where the help content (.md files) is located, relative to the root directory of the extension.
When CLI needs to show command line help for extension's command, it will search the docs directories of all extensions.
When CLI needs to show HTML help for the extension's commands, it will generate `html` directory right next to the docs dir in the extension.

Move extensibility.d.ts from {N} to mobile-cli-lib just to ensure correct transpilation.

Author: rosen-vladimirov

lib/common

@@ -35,7 +35,16 @@ export class ExtensibilityService implements IExtensibilityService {
 		const installResultInfo = await this.$npm.install(packageName, this.pathToExtensions, npmOpts);
 		this.$logger.trace(`Finished installation of extension '${extensionName}'. Trying to load it now.`);
 
-		return { extensionName: installResultInfo.name };
+		const packageJsonData = this.getExtensionPackageJsonData(installResultInfo.name);
+
+		const pathToExtension = this.getPathToExtension(extensionName);
+		const docs = packageJsonData && packageJsonData.nativescript && packageJsonData.nativescript.docs && path.join(pathToExtension, packageJsonData.nativescript.docs);
+		return {
+			extensionName: installResultInfo.name,
+			version: installResultInfo.version,
+			docs,
+			pathToExtension
+		};
 	}
 
 	@exported("extensibilityService")
@@ -49,8 +58,15 @@ export class ExtensibilityService implements IExtensibilityService {
 		this.$logger.trace(`Finished uninstallation of extension '${extensionName}'.`);
 	}
 
+	public getInstalledExtensionsData(): IExtensionData[] {
+		const installedExtensions = this.getInstalledExtensions();
+		return _.keys(installedExtensions).map(installedExtension => {
+			return this.getInstalledExtensionData(installedExtension);
+		});
+	}
+
 	@exported("extensibilityService")
-	public loadExtensions(): Promise<any>[] {
+	public loadExtensions(): Promise<IExtensionData>[] {
 		this.$logger.trace("Loading extensions.");
 
 		let dependencies: IStringDictionary = null;
@@ -74,14 +90,26 @@ export class ExtensibilityService implements IExtensibilityService {
 		return null;
 	}
 
+	private getInstalledExtensionData(extensionName: string): IExtensionData {
+		const packageJsonData = this.getExtensionPackageJsonData(extensionName);
+		const pathToExtension = this.getPathToExtension(extensionName);
+		const docs = packageJsonData && packageJsonData.nativescript && packageJsonData.nativescript.docs && path.join(pathToExtension, packageJsonData.nativescript.docs);
+		return {
+			extensionName: packageJsonData.name,
+			version: packageJsonData.version,
+			docs,
+			pathToExtension
+		};
+	}
+
 	@exported("extensibilityService")
 	public async loadExtension(extensionName: string): Promise<IExtensionData> {
 		try {
 			await this.assertExtensionIsInstalled(extensionName);
 
-			const pathToExtension = path.join(this.pathToExtensions, constants.NODE_MODULES_FOLDER_NAME, extensionName);
+			const pathToExtension = this.getPathToExtension(extensionName);
 			this.$requireService.require(pathToExtension);
-			return { extensionName };
+			return this.getInstalledExtensionData(extensionName);
 		} catch (error) {
 			this.$logger.warn(`Error while loading ${extensionName} is: ${error.message}`);
 			const err = <IExtensionLoadingError>new Error(`Unable to load extension ${extensionName}. You will not be able to use the functionality that it adds. Error: ${error.message}`);
@@ -90,6 +118,17 @@ export class ExtensibilityService implements IExtensibilityService {
 		}
 	}
 
+	private getPathToExtension(extensionName: string): string {
+		return path.join(this.pathToExtensions, constants.NODE_MODULES_FOLDER_NAME, extensionName);
+	}
+
+	private getExtensionPackageJsonData(extensionName: string): any {
+		const pathToExtension = this.getPathToExtension(extensionName);
+		const pathToPackageJson = path.join(pathToExtension, constants.PACKAGE_JSON_FILE_NAME);
+		const jsonData = this.$fs.readJson(pathToPackageJson);
+		return jsonData;
+	}
+
 	private async assertExtensionIsInstalled(extensionName: string): Promise<void> {
 		this.$logger.trace(`Asserting extension ${extensionName} is installed.`);
 		const installedExtensions = this.$fs.readDirectory(path.join(this.pathToExtensions, constants.NODE_MODULES_FOLDER_NAME));

lib/definitions/extensibility.d.ts

@@ -18,7 +18,9 @@ describe("extensibilityService", () => {
 
 	const getTestInjector = (): IInjector => {
 		const testInjector = new Yok();
-		testInjector.register("fs", {});
+		testInjector.register("fs", {
+			readJson: (pathToFile: string): any => ({})
+		});
 		testInjector.register("logger", stubs.LoggerStub);
 		testInjector.register("npm", {});
 		testInjector.register("settingsService", SettingsService);
@@ -28,6 +30,33 @@ describe("extensibilityService", () => {
 		return testInjector;
 	};
 
+	const getExpectedInstallationPathForExtension = (testInjector: IInjector, extensionName: string): string => {
+		const settingsService = testInjector.resolve<ISettingsService>("settingsService");
+		const profileDir = settingsService.getProfileDir();
+
+		return path.join(profileDir, "extensions", "node_modules", extensionName);
+	};
+
+	const mockFsReadJson = (testInjector: IInjector, extensionNames: string[]): void => {
+		const fs = testInjector.resolve<IFileSystem>("fs");
+		fs.readJson = (filename: string, encoding?: string): any => {
+			const extensionName = _.find(extensionNames, extName => filename.indexOf(extName) !== -1);
+			if (extensionName) {
+				return {
+					name: extensionName,
+					version: "1.0.0"
+				};
+			}
+
+			const dependencies: any = {};
+			_.each(extensionNames, name => {
+				dependencies[name] = "1.0.0";
+			});
+
+			return { dependencies };
+		};
+	};
+
 	describe("installExtension", () => {
 		describe("fails", () => {
 			it("when extensions dir does not exist and trying to create it fails", async () => {
@@ -133,17 +162,20 @@ describe("extensibilityService", () => {
 		it("returns the name of the installed extension", async () => {
 			const extensionName = "extension1";
 			const testInjector = getTestInjector();
+
 			const fs: IFileSystem = testInjector.resolve("fs");
 			fs.exists = (pathToCheck: string): boolean => path.basename(pathToCheck) !== extensionName;
 
 			fs.readDirectory = (dir: string): string[] => [extensionName];
 
+			fs.readJson = () => ({ name: extensionName, version: "1.0.0" });
+
 			const npm: INodePackageManager = testInjector.resolve("npm");
-			npm.install = async (packageName: string, pathToSave: string, config?: any): Promise<any> => ({ name: extensionName });
+			npm.install = async (packageName: string, pathToSave: string, config?: any): Promise<any> => ({ name: extensionName, version: "1.0.0" });
 
 			const extensibilityService: IExtensibilityService = testInjector.resolve(ExtensibilityService);
 			const actualResult = await extensibilityService.installExtension(extensionName);
-			assert.deepEqual(actualResult, { extensionName });
+			assert.deepEqual(actualResult, { extensionName, version: "1.0.0", docs: undefined, pathToExtension: getExpectedInstallationPathForExtension(testInjector, extensionName) });
 		});
 	});
 
@@ -160,16 +192,16 @@ describe("extensibilityService", () => {
 					return extensionNames;
 				};
 
-				fs.readJson = (filename: string, encoding?: string): any => {
-					const dependencies: any = {};
-					_.each(extensionNames, name => {
-						dependencies[name] = "1.0.0";
-					});
-
-					return { dependencies };
-				};
+				mockFsReadJson(testInjector, extensionNames);
 
-				const expectedResults: IExtensionData[] = _.map(extensionNames, extensionName => ({ extensionName }));
+				const expectedResults: IExtensionData[] = _.map(extensionNames, extensionName => (
+					{
+						extensionName,
+						version: "1.0.0",
+						pathToExtension: getExpectedInstallationPathForExtension(testInjector, extensionName),
+						docs: undefined
+					}
+				));
 
 				const extensibilityService: IExtensibilityService = testInjector.resolve(ExtensibilityService);
 				const actualResult = await Promise.all(extensibilityService.loadExtensions());
@@ -194,14 +226,7 @@ describe("extensibilityService", () => {
 					}
 				};
 
-				fs.readJson = (filename: string, encoding?: string): any => {
-					const dependencies: any = {};
-					_.each(extensionNames, name => {
-						dependencies[name] = "1.0.0";
-					});
-
-					return { dependencies };
-				};
+				mockFsReadJson(testInjector, extensionNames);
 
 				let isNpmInstallCalled = false;
 				const npm: INodePackageManager = testInjector.resolve("npm");
@@ -211,7 +236,7 @@ describe("extensibilityService", () => {
 					return { name: packageName };
 				};
 
-				const expectedResults: IExtensionData[] = _.map(extensionNames, extensionName => ({ extensionName }));
+				const expectedResults: IExtensionData[] = _.map(extensionNames, extensionName => ({ extensionName, version: "1.0.0", pathToExtension: getExpectedInstallationPathForExtension(testInjector, extensionName), docs: undefined }));
 
 				const extensibilityService: IExtensibilityService = testInjector.resolve(ExtensibilityService);
 				const actualResult = await Promise.all(extensibilityService.loadExtensions());
@@ -230,14 +255,7 @@ describe("extensibilityService", () => {
 					return extensionNames;
 				};
 
-				fs.readJson = (filename: string, encoding?: string): any => {
-					const dependencies: any = {};
-					_.each(extensionNames, name => {
-						dependencies[name] = "1.0.0";
-					});
-
-					return { dependencies };
-				};
+				mockFsReadJson(testInjector, extensionNames);
 
 				const requireService: IRequireService = testInjector.resolve("requireService");
 				requireService.require = (module: string) => {
@@ -246,7 +264,7 @@ describe("extensibilityService", () => {
 					}
 				};
 
-				const expectedResults: any[] = _.map(extensionNames, extensionName => ({ extensionName }));
+				const expectedResults: any[] = _.map(extensionNames, extensionName => ({ extensionName, version: "1.0.0", pathToExtension: getExpectedInstallationPathForExtension(testInjector, extensionName), docs: undefined }));
 				expectedResults[0] = new Error("Unable to load extension extension1. You will not be able to use the functionality that it adds. Error: Unable to load module.");
 				const extensibilityService: IExtensibilityService = testInjector.resolve(ExtensibilityService);
 				const promises = extensibilityService.loadExtensions();
@@ -269,14 +287,7 @@ describe("extensibilityService", () => {
 				const fs: IFileSystem = testInjector.resolve("fs");
 				const expectedErrorMessage = `Unable to read ${constants.NODE_MODULES_FOLDER_NAME} dir.`;
 				fs.exists = (pathToCheck: string): boolean => path.basename(pathToCheck) === "extensions" || path.basename(pathToCheck) === constants.PACKAGE_JSON_FILE_NAME;
-				fs.readJson = (filename: string, encoding?: string): any => {
-					const dependencies: any = {};
-					_.each(extensionNames, name => {
-						dependencies[name] = "1.0.0";
-					});
-
-					return { dependencies };
-				};
+				mockFsReadJson(testInjector, extensionNames);
 
 				let isReadDirCalled = false;
 				fs.readDirectory = (dir: string): string[] => {
@@ -310,14 +321,7 @@ describe("extensibilityService", () => {
 					"expected 'extension3' to deeply equal 'extension1'"];
 				const fs: IFileSystem = testInjector.resolve("fs");
 				fs.exists = (pathToCheck: string): boolean => path.basename(pathToCheck) === "extensions" || path.basename(pathToCheck) === constants.PACKAGE_JSON_FILE_NAME;
-				fs.readJson = (filename: string, encoding?: string): any => {
-					const dependencies: any = {};
-					_.each(extensionNames, name => {
-						dependencies[name] = "1.0.0";
-					});
-
-					return { dependencies };
-				};
+				mockFsReadJson(testInjector, extensionNames);
 
 				let isReadDirCalled = false;
 				fs.readDirectory = (dir: string): string[] => {