Escape back-slashes as part of escapeString fn

Author: blakeembrey

index.js

@@ -223,7 +223,7 @@ function tokensToFunction (tokens) {
  * @return {string}
  */
 function escapeString (str) {
-  return str.replace(/([.+*?=^!:${}()[\]|\/])/g, '\\$1')
+  return str.replace(/([.+*?=^!:${}()[\]|\/\\])/g, '\\$1')
 }
 
 /**

test.ts

@@ -1497,6 +1497,28 @@ var TESTS: Test[] = [
       [{ '0': '123' }, '/123']
     ]
   ],
+  [
+    '/route\\(\\\\(\\d+\\\\)\\)',
+     null,
+    [
+      '/route(\\',
+      {
+        name: 0,
+        prefix: '',
+        delimiter: '/',
+        optional: false,
+        repeat: false,
+        partial: false,
+        asterisk: false,
+        pattern: '\\d+\\\\'
+      },
+      ')'
+    ],
+    [
+      ['/route(\\123\\)', ['/route(\\123\\)', '123\\']]
+    ],
+    []
+  ],
 
   /**
    * Regexps.