diff --git a/src/core/speedy-feature-tracker.js b/src/core/speedy-feature-tracker.js
index 5bf152f4..5944377d 100644
--- a/src/core/speedy-feature-tracker.js
+++ b/src/core/speedy-feature-tracker.js
@@ -299,6 +299,6 @@ export class LKFeatureTracker extends SpeedyFeatureTracker
         if(typeof threshold !== 'number')
             throw new IllegalArgumentError(`Invalid discardThreshold`);
 
-        this._discardThreshold = Math.max(0, +threshold);
+        this._discardThreshold = Math.max(0, threshold);
     }
 }
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