diff --git a/src/lib/run-dev.js b/src/lib/run-dev.js
index 1352d76..972ed50 100644
--- a/src/lib/run-dev.js
+++ b/src/lib/run-dev.js
@@ -554,7 +554,10 @@ function interpolate (valueString, props) {
   // replace ${VAR_NAME}, $VAR_NAME, or {VAR_NAME} with values from props, but not if they are enclosed in quotes
   // if key is not found on props, the value is returned as is (no replacement)
   const retStr = valueString.replace(/(?<!['"`])\$\{(\w+)\}(?!['"`])|(?<!['"`])\$(\w+)(?!['"`])|(?<!['"`])\{(\w+)\}(?!['"`])/g,
-    (_, varName1, varName2, varName3) => props[varName1 || varName2 || varName3] || _)
+    (_, varName1, varName2, varName3) => {
+      const varName = varName1 || varName2 || varName3
+      return Object.prototype.hasOwnProperty.call(props, varName) ? props[varName] : ''
+    })
   return retStr
 }
 
diff --git a/test/lib/run-dev.test.js b/test/lib/run-dev.test.js
index 375d71b..550b71a 100644
--- a/test/lib/run-dev.test.js
+++ b/test/lib/run-dev.test.js
@@ -348,7 +348,7 @@ describe('createActionParametersFromRequest', () => {
       justDollar: 'value is world',
       mustache: 'value is world',
       literal: 'value is literally "${mustache}" and "{mustache}"',
-      doesNotExist: 'value is ${doesNotExist}'
+      doesNotExist: 'value is '
     })
     delete process.env.mustache
   })