diff --git a/pkg/argus_wasm_bg.wasm b/pkg/argus_wasm_bg.wasm
index ba162db..ec3309f 100644
Binary files a/pkg/argus_wasm_bg.wasm and b/pkg/argus_wasm_bg.wasm differ
diff --git a/src/lib.rs b/src/lib.rs
index cb574c7..0907bbd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -19,7 +19,7 @@ use std::time::Duration;
 use web_sys::console;
 
 struct TraceMap<'a> {
-    traces: HashMap<&'a str, Signal<f64>>,
+    traces: HashMap<&'a str, Signal<bool>>,
 }
 
 impl<'a> Trace for TraceMap<'a> {
@@ -40,7 +40,7 @@ impl<'a> Trace for TraceMap<'a> {
 #[derive(Serialize, Deserialize)]
 pub struct StateBuddyTraceEntry {
     simtime: f64,
-    state: HashMap<String, f64>,
+    state: HashMap<String, bool>,
     // inputEvent: String,
     // outputEvents: Vec<String>,
 }
@@ -57,14 +57,14 @@ pub fn eval_boolean(s: &str, js_trace: JsValue) -> JsValue {
         Ok(trace) => trace,
         Err(e) => return JsValue::from_str(("failed to parse JSON: ".to_owned() + &e.to_string()).as_str()),
     };
-    let mut traceMap = HashMap::<&str, Signal<f64>>::new();
+    let mut traceMap = HashMap::<&str, Signal<bool>>::new();
     for entry in &trace.entries {
         for (prop, val) in &entry.state {
-            let signal = traceMap.entry(prop.as_str()).or_insert_with(|| Signal::<f64>::Sampled {
+            let signal: &mut Signal<bool> = traceMap.entry(prop.as_str()).or_insert_with(|| Signal::<bool>::Sampled {
                 values: vec![],
                 time_points: vec![],
             });
-            if let Signal::<f64>::Sampled { values, time_points } = signal {
+            if let Signal::<bool>::Sampled { values, time_points } = signal {
                 values.push(*val);
                 time_points.push(Duration::from_secs(entry.simtime as u64));
             }
@@ -76,12 +76,12 @@ pub fn eval_boolean(s: &str, js_trace: JsValue) -> JsValue {
     let m = TraceMap{traces: traceMap};
     for name in m.signal_names() {
         console::debug_2(&JsValue::from_str("signal name:"), &JsValue::from_str(name));
-        let signal: &Signal<f64> = m.get(name).expect("bla");
-        if let Signal::<f64>::Sampled { values, time_points } = signal {
+        let signal: &Signal<bool> = m.get(name).expect("bla");
+        if let Signal::<bool>::Sampled { values, time_points } = signal {
             for i in 0..(values.len()) {
                 console::debug_2(
                     &JsValue::from_f64(time_points[i].as_millis() as f64),
-                    &JsValue::from_f64(values[i]));
+                    &JsValue::from_bool(values[i]));
             }
         }
     }