diff --git a/.gitignore b/.gitignore
index 49b3073eefbf1f5035d839aaa18754fec0a13d45..b8629cee13886923757d31c1aad1554a0f3af992 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,5 @@ native/artifacts.json
 **/.DS_Store
 
 *.bk
+
+*.wot
diff --git a/lib/index.js b/lib/index.js
index ab3e2715bb150865b1f8e276e66cc6cd2e9f5da6..baa4804451b566191384009f5212dbcbe9f8800d 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1,3 +1,16 @@
-var addon = require('../native');
+let WebOfTrust = require('../native').WebOfTrust;
 
-console.log(addon.hello());
+{
+    let wot = new WebOfTrust(3);
+    console.log(wot.add_node());
+    console.log(wot.size())
+}
+
+{
+    let wot = new WebOfTrust("hey.wot");
+
+    console.log("Hello, world !");
+    console.log(wot.add_node());
+    console.log(wot.size());
+    console.log(wot.to_file("hey.wot"));
+}
diff --git a/native/src/lib.rs b/native/src/lib.rs
index 0a475ad1eb3f7e3cd452c5854ed05345dc581e7d..e937989a942693ea319b2e6b822cfc25fec3c187 100644
--- a/native/src/lib.rs
+++ b/native/src/lib.rs
@@ -4,7 +4,7 @@
 extern crate neon;
 extern crate duniter_rs_wotb;
 
-use neon::js::{Value, JsInteger, JsString, JsBoolean, JsFunction, JsArray, JsNumber, Object};
+use neon::js::{Value, JsInteger, JsString, JsBoolean, JsFunction, JsArray, JsNumber, JsObject, Object};
 use neon::js::class::{Class, JsClass};
 use neon::mem::Handle;
 use neon::vm::{Throw, Lock};
@@ -19,14 +19,14 @@ declare_types! {
             let scope = call.scope;
             let arg0 = try!(call.arguments.require(scope, 0));
 
-            if let Ok(max_cert) = arg0.check::<JsInteger>() {
+            if let Some(max_cert) = arg0.downcast::<JsInteger>() {
                 let max_cert = max_cert.value();
 
                 match max_cert > 0 {
                     true => Ok(WebOfTrust::new(max_cert as usize)),
                     false => Err(Throw),
                 }
-            } else if let Ok(path) = arg0.check::<JsString>() {
+            } else if let Some(path) = arg0.downcast::<JsString>() {
                 let path = path.value();
 
                 match WebOfTrust::from_file(path.as_str()) {