fill README more

README.md

@@ -8,20 +8,32 @@ A Ruby wrapper for [QuickJS](https://bellard.org/quickjs) to run JavaScript code
 gem install quickjs
 ```
 
-```
+```rb
 gem 'quickjs'
 ```
 
-## Features
+## Usage
 
-### Evaluate JavaScript code
+### `Quickjs.evalCode`: Evaluate JavaScript code
 
 ```rb
 require 'quickjs'
 
 Quickjs.evalCode('const fn = (n, pow) => n ** pow; fn(2,8);') # => 256
+Quickjs.evalCode('const fn = (name) => `Hi, ${name}!`; fn("Itadori");') # => "Hi, Itadori!
+Quickjs.evalCode("const isOne = (n) => 1 === n; func(1);") #=> true (TruleClass)
+Quickjs.evalCode("const isOne = (n) => 1 === n; func(3);") #=> false (FalseClass)
+
+# If the result returns 'object' for typeof, consumes it via JSON.stringify (JS) -> JSON.parse (Ruby)
+Quickjs.evalCode("[1,2,3]") #=> [1, 2, 3] (Array)
+Quickjs.evalCode("({ a: '1', b: 1 })") #=> { 'a' => '1', 'b' => 1 } (Hash)
+
+Quickjs.evalCode("null") #=> nil
+Quickjs.evalCode('const obj = {}; obj.missingKey;') # => :undefined (Quickjs::Value::Undefined)
+Quickjs.evalCode("Number('whatever')") #=> :NaN (Quickjs::Value::NAN)
 ```
 
 ## License
 
-Every file in `ext/quickjsrb/quickjs` is licensed under [the MIT License Copyright 2017-2021 by Fabrice Bellard and Charlie Goron](/ext/quickjsrb/quickjs/LICENSE). For otherwise, [the MIT License, Copyright 2024 by Kengo Hamasaki](/LICENSE).
+Every file in `ext/quickjsrb/quickjs` is licensed under [the MIT License Copyright 2017-2021 by Fabrice Bellard and Charlie Goron](/ext/quickjsrb/quickjs/LICENSE).
+For otherwise, [the MIT License, Copyright 2024 by Kengo Hamasaki](/LICENSE).