diff --git a/src/JShrink/Minifier.php b/src/JShrink/Minifier.php
index 10b035f..4986c53 100644
--- a/src/JShrink/Minifier.php
+++ b/src/JShrink/Minifier.php
@@ -285,7 +285,14 @@ protected function loop()
 
             if ($this->b == '/') {
                 $valid_tokens = "(,=:[!&|?\n";
-                if (strpos($valid_tokens, $this->last_char) !== false || strpos($valid_tokens, $this->a) !== false) {
+
+                # Find last "real" token, excluding spaces.
+                $last_token = $this->a;
+                if ($last_token == " ") {
+                    $last_token = $this->last_char;
+                }
+
+                if (strpos($valid_tokens, $last_token) !== false) {
                     // Regex can appear unquoted after these symbols
                     $this->saveRegex();
                 } else if ($this->endsInKeyword()) {
@@ -644,11 +651,15 @@ protected static function isAlphaNumeric($char)
     }
 
     protected function endsInKeyword() {
+
+        # When this function is called A is not yet assigned to output.
+        $testOutput = $this->output . $this->a;
+
         foreach(static::$keywords as $keyword) {
-            if (str_ends_with($this->output, $keyword)) {
+            if (str_ends_with($testOutput, $keyword)) {
                 return true;
             }
-            if (str_ends_with($this->output, $keyword . " ")) {
+            if (str_ends_with($testOutput, $keyword . " ")) {
                 return true;
             }
         }
diff --git a/tests/Resources/jshrink/input/regex_detection.js b/tests/Resources/jshrink/input/regex_detection.js
new file mode 100644
index 0000000..6833207
--- /dev/null
+++ b/tests/Resources/jshrink/input/regex_detection.js
@@ -0,0 +1,5 @@
+function test () {
+  return this.indeterminate
+    ? 100
+    : (100 * (this.options.value - this.min)) / (this.options.max - this.min)
+}
diff --git a/tests/Resources/jshrink/input/regex_division.js b/tests/Resources/jshrink/input/regex_division.js
new file mode 100644
index 0000000..6d503e7
--- /dev/null
+++ b/tests/Resources/jshrink/input/regex_division.js
@@ -0,0 +1,3 @@
+if (D > (F/2)) {
+  console.log('a')
+}
diff --git a/tests/Resources/jshrink/input/regex_keyword_similarity.js b/tests/Resources/jshrink/input/regex_keyword_similarity.js
new file mode 100644
index 0000000..9f79ba7
--- /dev/null
+++ b/tests/Resources/jshrink/input/regex_keyword_similarity.js
@@ -0,0 +1 @@
+var value = currentRating/other
\ No newline at end of file
diff --git a/tests/Resources/jshrink/output/regex_detection.js b/tests/Resources/jshrink/output/regex_detection.js
new file mode 100644
index 0000000..be38d46
--- /dev/null
+++ b/tests/Resources/jshrink/output/regex_detection.js
@@ -0,0 +1 @@
+function test(){return this.indeterminate?100:(100*(this.options.value-this.min))/(this.options.max-this.min)}
\ No newline at end of file
diff --git a/tests/Resources/jshrink/output/regex_division.js b/tests/Resources/jshrink/output/regex_division.js
new file mode 100644
index 0000000..70fa287
--- /dev/null
+++ b/tests/Resources/jshrink/output/regex_division.js
@@ -0,0 +1 @@
+if(D>(F/2)){console.log('a')}
\ No newline at end of file
diff --git a/tests/Resources/jshrink/output/regex_keyword_similarity.js b/tests/Resources/jshrink/output/regex_keyword_similarity.js
new file mode 100644
index 0000000..24796c2
--- /dev/null
+++ b/tests/Resources/jshrink/output/regex_keyword_similarity.js
@@ -0,0 +1 @@
+var value=currentRating/other
\ No newline at end of file