Updated jsonnet readme

JS/jsonnet/README.md

@@ -6,14 +6,15 @@ This project aim to running Jsonnet in Wasm. The code is written in Rust and com
 
 -   [x] Jsonnet Snippet evaluation
 -   [x] External variable support
--   [ ] External function support
+-   [x] External function support
 -   [x] Jsonnet file evaluation
 
 ## Usage
 
 ```bash
 npm install arakoo-jsonnet
 ```
+### You can evaluate snippet as follows -
 
 ```javascript
 import Jsonnet from "arakoo-jsonnet";
@@ -47,6 +48,33 @@ console.log(result);
     }
 }
 ```
+### You can evaluate functions directly from jsonnet as follows -
+
+```javascript
+  import Jsonnet from "arakoo-jsonnet";
+
+  let jsonnet = new Jsonnet();
+  function addSomeNumber(a, b, c) {
+    return a+b+c
+  }
+  let result = jsonnet
+  .javascriptCallback("addSomeNumber",addSomeNumber)
+  .evaluateSnippet(`{
+        result : arakoo.native("addSomeNumber")(3,4,5)
+    }`)
+```
+First you need to register the javascript function you wish to call from jsonnet by calling javascriptCallback method of jsonnet instance . Then you can call the registered function by using arakoo.native method.
+
+### Output
+```json
+{
+  "result": "12"
+}
+```
+
+> Note - 
+>1. You can only return string from the function which you are calling from jsonnet . If you need to return any other type than you can JSON.stringify it and then std.parseJson in jsonnet. 
+>2. You need to add  ```--experimental-wasm-modules``` flag while running the js file where you imported / required this jsonnet package
 
 ## Build
 

JS/jsonnet/package.json

@@ -1,6 +1,6 @@
 {
     "name": "@arakoodev/jsonnet",
-    "version": "0.3.0",
+    "version": "0.3.1",
     "exports": {
         "import": {
             "default": "./src/index.mjs",