README: improve description and code snippet

README.md

@@ -3,30 +3,32 @@
 [![codecov](https://codecov.io/github/harunou/to-flow-generator-function/branch/main/graph/badge.svg?token=1WTYGPJ8N5)](https://codecov.io/github/harunou/to-flow-generator-function)
 [![npm](https://img.shields.io/npm/v/to-flow-generator-function)](https://www.npmjs.com/package/to-flow-generator-function)
 
-Converts a promise-returning function to a generator-returning one. This is intended to allow for the usage of type-safe yield inside a MobX flow wrapper.
+The `toFlowGeneratorFunction` is a utility function that converts a promise-returning function into a generator-returning function. It is designed to enable the usage of type-safe `yield` statements inside MobX `flow` wrapper.
 
 ## Parameters
 
-- `fn`
+- `fn`: The promise-returning function to be converted into a generator-returning function.
 
 ## Examples
 
 ```typescript
+import { flow } from 'mobx';
+import { toFlowGeneratorFunction } from 'to-flow-generator-function';
 
 interface UserData {
     id: number;
     name: string;
     age: number;
 }
 
-const fetchUserName = (id: number) => Promise.resolve('John');
-const fetchUserAge = (id: number) => Promise.resolve(25);
+const fetchUserName = (id: number): Promise<string> => Promise.resolve('John');
+const fetchUserAge = (id: number): Promise<number> => Promise.resolve(25);
 
 function* fetchUserData(id: number): FlowGenerator<UserData> {
     const name = yield* toFlowGeneratorFunction(fetchUserName)(id);
-    // name is type of string
+    // Here, `name` has the type `string`.
     const age = yield* toFlowGeneratorFunction(fetchUserAge)(id);
-    // age is type of number
+    // Here, `age` has the type `number`.
     return {
         id,
         name,
@@ -36,7 +38,7 @@ function* fetchUserData(id: number): FlowGenerator<UserData> {
 
 const userId = 3;
 const userData = await flow(fetchUserData)(userId);
-
+// Here, `useData` has the type `UserData`.
 ```
 
 More examples in [toFlowGeneratorFunction.spec.ts](./src/toFlowGeneratorFunction.spec.ts)