Terminate loops after 1s timeout or 10,000 iterations

README.md

@@ -38,7 +38,7 @@ Modifies input code to do the following:
   executing loop should be broken
 * Injects into `for`, `while`, and `do-while` loops a call to `loopBreaker()`
 
-The loop is considered likely-infinite if the following two conditions hold:
+The loop is considered likely-infinite if either of the following two conditions is met:
 
 * The loop has executed at least ten thousand times
 * The loop has been running for at least one second of wall time
@@ -60,7 +60,7 @@ var __loopBreaker = (function() {
   return function() {
     startTime || (startTime = Date.now());
     count += 1;
-    if (count > 10000 && (Date.now() - startTime > 1000)) {
+    if (count > 10000 || (Date.now() - startTime > 1000)) {
       throw new Error("Loop Broken!");
     }
   };

src/index.js

@@ -19,7 +19,13 @@ const loopBreaker = recast.parse(`var __loopBreaker = (function() {
       }
 
       loop.count += 1;
-      if (loop.count > 10000 && (Date.now() - loop.startTime > 1000)) {
+      if (loop.count % 100 === 0) {
+        // Date math is slow, so only check every 100 loops
+        if (Date.now() - loop.startTime > 1000) {
+          throw new Error("Loop Broken!");
+        }
+      }
+      if (loop.count > 10000) {
         throw new Error("Loop Broken!");
       }
     },

test/index.js

@@ -51,6 +51,14 @@ testBrokenLoop('do-while with body', (c) => {
   } while (c());
 });
 
+testBrokenLoop('non-infinite slow code execution', () => {
+  const testStartTime = Date.now() + 2000;
+  function checkDate() {
+    return Date.now() - testStartTime < 2000;
+  }
+  while (checkDate()) void(0);
+});
+
 function testBrokenLoop(message, fn) {
   test(message, (assert) => {
     const startTime = Date.now();