update readme

README.md

@@ -1,4 +1,4 @@
-To get started:
+# To build:
 
 Download [emscripten](https://kripken.github.io/emscripten-site/index.html). I used portable SDK. You may need to change your `PATH` depending on how/what you install. If you download portable SDK, you can find SDK binaries (e.g. `emmake`) in `$SDK_ROOT/emsdk_portable/emscripten/$VERSION/`. Then run the following:
 
@@ -8,13 +8,43 @@ cd dbc2json.js
 emmake make
 ```
 
-To clean:
+# To use:
+
+After project is built, `dist/main.js` is created which exports a function called `run`:
+
+```c
+const char* run();
+```
+
+`run` function expects a DBC file at `/test.dbc` (memory based virtual FS). You can run the following in Javascript to create the file:
+
+```js
+// Assuming dbcFile is the string content of an actual dbc file
+FS.writeFile('/test.dbc', dbcFile);
+```
+
+### Example usage from browser:
+
+```html
+<script src="main.js"></script>
+<script>
+ ...
+ // Assuming dbcFile is the string content of an actual dbc file
+ var parse = Module.cwrap('run', 'string', []);
+ FS.writeFile('/test.dbc', dbcFile);
+ var output = parse();
+ FS.unlink('/test.dbc');
+ console.log(output);
+</script>
+```
+
+# To clean:
 
 ```shell
 make clean
 ```
 
-To force build (in case stuff gets out of sync):
+# To force build everything:
 
 ```shell
 emmake make -B