better example + API.md (wip)

README.md

@@ -11,15 +11,12 @@ npm install avro-crc64
 ```
 
 ## Documentation
-- API (tbd)
+- [API](docs/API.md)
 
 ## Examples
 
-One can find this example in the /examples folder.
-
 ```js
-/* example 1 */
-const { fingerprint64AvroSchema } = require('../src');
+const { fingerprint64AvroSchema } = require('avro-crc64');
 
 const avroSchemaExample = {
   type: 'record',
@@ -36,9 +33,8 @@ const avroSchemaExample = {
 
 fingerprint64AvroSchema(JSON.stringify(avroSchemaExample))
   .then((uint8) => {
-    const hexFingerprint = Buffer.from(uint8).toString('hex');
+    const hexFingerprint = Buffer.from(uint8.buffer).toString('hex');
 
     return console.log(hexFingerprint); // logs "b75d6f7da238cf70"
   })
-;
-```
+;```

docs/API.md

@@ -0,0 +1,15 @@
+# avro-crc64 API
+
+## fingerprint64AvroSchema(schemaString: string): Promise<Uint8Array>
+ fingerprint64AvroSchema returns a promise which resolves to a Rabin 64-bit crc fingerprint as 8 byte [Uint8Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array).
+
+### Parameters
+- schemaString<string>: [Apache AVRO](https://avro.apache.org/docs/current/) schema in string representation
+
+### Returns
+- Promise<Uint8Array>: 64-bit fingerprint
+
+### Errors
+The returned promise will reject with:
+- AvroSchemaStringSyntaxError<Error>: In case parsing of schemaString fails with a SytaxError Exception
+- InvalidAvroSchemaError<Error>: In case a [AVSC](https://github.com/mtth/avsc) AVRO Type could not be instantiated with parsed schemaString object.