Roughing out the demo app

node_modules/has-yarn/index.d.ts

@@ -0,0 +1,16 @@
+declare const hasYarn: {
+	/**
+	 * Check if a project is using [Yarn](https://yarnpkg.com).
+	 *
+	 * @param cwd - Current working directory. Default: `process.cwd()`.
+	 * @returns Whether the project uses Yarn.
+	 */
+	(cwd?: string): boolean;
+
+	// TODO: Remove this for the next major release, refactor the whole definition to:
+	// declare function hasYarn(cwd?: string): boolean;
+	// export = hasYarn;
+	default: typeof hasYarn;
+};
+
+export = hasYarn;