diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5eeb036..82215e1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,10 @@
 # Changelog
 
+## Unreleased
+
+- `agent.js` no longer uses a numeric separator (`60_000`), which
+  webpack 4 cannot parse. Kept identical to @hibira-io/vue.
+
 ## 0.3.0
 
 - `HibiraProvider` takes a `Pusher` prop, the pusher-js class to open the
diff --git a/agent.js b/agent.js
index 2c2a404..7350d68 100644
--- a/agent.js
+++ b/agent.js
@@ -31,7 +31,7 @@ export const AGENT_EVENTS = [
   CHUNK_EVENT,
 ];
 
-const CHUNK_TTL = 60_000;
+const CHUNK_TTL = 60000;
 const SEEN_MAX = 5000;
 
 /**