diff --git a/lighthouse-core/gather/driver.js b/lighthouse-core/gather/driver.js
index 693d4b1c925b..a48327b02414 100644
--- a/lighthouse-core/gather/driver.js
+++ b/lighthouse-core/gather/driver.js
@@ -115,7 +115,7 @@ class Driver {
    * @return {Promise<number>}
    */
   getBenchmarkIndex() {
-    return this.evaluateAsync(`(${pageFunctions.ultradumbBenchmark.toString()})()`);
+    return this.evaluateAsync(`(${pageFunctions.ultradumbBenchmarkString})()`);
   }
 
   /**
@@ -302,7 +302,7 @@ class Driver {
           return new __nativePromise(function (resolve) {
             return __nativePromise.resolve()
               .then(_ => ${expression})
-              .catch(${pageFunctions.wrapRuntimeEvalErrorInBrowser.toString()})
+              .catch(${pageFunctions.wrapRuntimeEvalErrorInBrowserString})
               .then(resolve);
           });
         }())`,
@@ -513,7 +513,7 @@ class Driver {
     let lastTimeout;
     let cancelled = false;
 
-    const checkForQuietExpression = `(${pageFunctions.checkTimeSinceLastLongTask.toString()})()`;
+    const checkForQuietExpression = `(${pageFunctions.checkTimeSinceLastLongTaskString})()`;
     /**
      * @param {Driver} driver
      * @param {() => void} resolve
@@ -1137,7 +1137,7 @@ class Driver {
    * @return {Promise<void>}
    */
   async registerPerformanceObserver() {
-    const scriptStr = `(${pageFunctions.registerPerformanceObserverInPage.toString()})()`;
+    const scriptStr = `(${pageFunctions.registerPerformanceObserverInPageString})()`;
     await this.evaluateScriptOnNewDocument(scriptStr);
   }
 
diff --git a/lighthouse-core/gather/gatherers/accessibility.js b/lighthouse-core/gather/gatherers/accessibility.js
index 8ec0112983d1..452f0d95ee20 100644
--- a/lighthouse-core/gather/gatherers/accessibility.js
+++ b/lighthouse-core/gather/gatherers/accessibility.js
@@ -96,7 +96,7 @@ class Accessibility extends Gatherer {
   afterPass(passContext) {
     const driver = passContext.driver;
     const expression = `(function () {
-      ${pageFunctions.getOuterHTMLSnippet.toString()};
+      ${pageFunctions.getOuterHTMLSnippetString};
       ${axeLibSource};
       return (${runA11yChecks.toString()}());
     })()`;
diff --git a/lighthouse-core/gather/gatherers/dobetterweb/anchors-with-no-rel-noopener.js b/lighthouse-core/gather/gatherers/dobetterweb/anchors-with-no-rel-noopener.js
index d2beb9473838..18ff463b91ef 100644
--- a/lighthouse-core/gather/gatherers/dobetterweb/anchors-with-no-rel-noopener.js
+++ b/lighthouse-core/gather/gatherers/dobetterweb/anchors-with-no-rel-noopener.js
@@ -15,8 +15,8 @@ class AnchorsWithNoRelNoopener extends Gatherer {
    */
   afterPass(passContext) {
     const expression = `(function() {
-      ${pageFunctions.getOuterHTMLSnippet.toString()};
-      ${pageFunctions.getElementsInDocument.toString()}; // define function on page
+      ${pageFunctions.getOuterHTMLSnippetString};
+      ${pageFunctions.getElementsInDocumentString}; // define function on page
       const selector = 'a[target="_blank"]:not([rel~="noopener"]):not([rel~="noreferrer"])';
       const elements = getElementsInDocument(selector);
       return elements.map(node => ({
diff --git a/lighthouse-core/gather/gatherers/dobetterweb/domstats.js b/lighthouse-core/gather/gatherers/dobetterweb/domstats.js
index 866e7b633563..a949ca90496a 100644
--- a/lighthouse-core/gather/gatherers/dobetterweb/domstats.js
+++ b/lighthouse-core/gather/gatherers/dobetterweb/domstats.js
@@ -140,7 +140,7 @@ class DOMStats extends Gatherer {
    */
   afterPass(passContext) {
     const expression = `(function() {
-      ${pageFunctions.getOuterHTMLSnippet.toString()};
+      ${pageFunctions.getOuterHTMLSnippetString};
       ${createSelectorsLabel.toString()};
       ${elementPathInDOM.toString()};
       return (${getDOMStats.toString()}(document.documentElement));
diff --git a/lighthouse-core/gather/gatherers/dobetterweb/password-inputs-with-prevented-paste.js b/lighthouse-core/gather/gatherers/dobetterweb/password-inputs-with-prevented-paste.js
index 6b50a0e7b189..f6aecee39f5a 100644
--- a/lighthouse-core/gather/gatherers/dobetterweb/password-inputs-with-prevented-paste.js
+++ b/lighthouse-core/gather/gatherers/dobetterweb/password-inputs-with-prevented-paste.js
@@ -35,7 +35,7 @@ class PasswordInputsWithPreventedPaste extends Gatherer {
    */
   afterPass(passContext) {
     return passContext.driver.evaluateAsync(`(() => {
-      ${pageFunctions.getOuterHTMLSnippet.toString()};
+      ${pageFunctions.getOuterHTMLSnippetString};
       return (${findPasswordInputsWithPreventedPaste.toString()}());
     })()`);
   }
diff --git a/lighthouse-core/gather/gatherers/image-usage.js b/lighthouse-core/gather/gatherers/image-usage.js
index c3f89ccbfe1c..0f97537135fd 100644
--- a/lighthouse-core/gather/gatherers/image-usage.js
+++ b/lighthouse-core/gather/gatherers/image-usage.js
@@ -161,7 +161,7 @@ class ImageUsage extends Gatherer {
     }, /** @type {Object<string, LH.Artifacts.SingleImageUsage['networkRecord']>} */ ({}));
 
     const expression = `(function() {
-      ${pageFunctions.getElementsInDocument.toString()}; // define function on page
+      ${pageFunctions.getElementsInDocumentString}; // define function on page
       return (${collectImageElementInfo.toString()})();
     })()`;
 
diff --git a/lighthouse-core/gather/gatherers/seo/crawlable-links.js b/lighthouse-core/gather/gatherers/seo/crawlable-links.js
index 12354fa4dcb2..e0ead7b60478 100644
--- a/lighthouse-core/gather/gatherers/seo/crawlable-links.js
+++ b/lighthouse-core/gather/gatherers/seo/crawlable-links.js
@@ -15,7 +15,7 @@ class CrawlableLinks extends Gatherer {
    */
   afterPass(passContext) {
     const expression = `(function() {
-      ${pageFunctions.getElementsInDocument.toString()}; // define function on page
+      ${pageFunctions.getElementsInDocumentString}; // define function on page
       const selector = 'a[href]:not([rel~="nofollow"])';
       const elements = getElementsInDocument(selector);
       return elements
diff --git a/lighthouse-core/gather/gatherers/seo/embedded-content.js b/lighthouse-core/gather/gatherers/seo/embedded-content.js
index da87171268e1..281aa1c40438 100644
--- a/lighthouse-core/gather/gatherers/seo/embedded-content.js
+++ b/lighthouse-core/gather/gatherers/seo/embedded-content.js
@@ -15,7 +15,7 @@ class EmbeddedContent extends Gatherer {
    */
   afterPass(passContext) {
     const expression = `(function() {
-      ${pageFunctions.getElementsInDocument.toString()}; // define function on page
+      ${pageFunctions.getElementsInDocumentString}; // define function on page
       const selector = 'object, embed, applet';
       const elements = getElementsInDocument(selector);
       return elements
diff --git a/lighthouse-core/lib/page-functions.js b/lighthouse-core/lib/page-functions.js
index eee83cd9ddf6..f0d05ff0b389 100644
--- a/lighthouse-core/lib/page-functions.js
+++ b/lighthouse-core/lib/page-functions.js
@@ -145,10 +145,11 @@ function ultradumbBenchmark() {
 }
 
 module.exports = {
-  wrapRuntimeEvalErrorInBrowser,
-  registerPerformanceObserverInPage,
-  checkTimeSinceLastLongTask,
-  getElementsInDocument,
-  getOuterHTMLSnippet,
-  ultradumbBenchmark,
+  wrapRuntimeEvalErrorInBrowserString: wrapRuntimeEvalErrorInBrowser.toString(),
+  registerPerformanceObserverInPageString: registerPerformanceObserverInPage.toString(),
+  checkTimeSinceLastLongTaskString: checkTimeSinceLastLongTask.toString(),
+  getElementsInDocumentString: getElementsInDocument.toString(),
+  getOuterHTMLSnippetString: getOuterHTMLSnippet.toString(),
+  ultradumbBenchmark: ultradumbBenchmark,
+  ultradumbBenchmarkString: ultradumbBenchmark.toString(),
 };