Add example preact.config.js

Author: wub

src/preact.config.js

@@ -0,0 +1,13 @@
+import preactCliTypeScript from "preact-cli-plugin-typescript";
+
+/**
+ * Function that mutates original webpack config.
+ * Supports asynchronous changes when promise is returned.
+ *
+ * @param {object} config original webpack config.
+ * @param {object} env options passed to CLI.
+ * @param {WebpackConfigHelpers} helpers object with useful helpers when working with config.
+ **/
+export default function (config, env, helpers) {
+	preactCliTypeScript(config);
+}