Allow delimiter to be set for tokensToRegExp

Closes pillarjs#96

index.d.ts

@@ -20,6 +20,10 @@ declare namespace pathToRegexp {
      * When `false` the path will match at the beginning. (default: `true`)
      */
     end?: boolean;
+    /**
+     * Sets the final character for non-ending optimistic matches. (default: `/`)
+     */
+    delimiter?: string;
   }
 
   export interface ParseOptions {

index.js

@@ -341,8 +341,6 @@ function tokensToRegExp (tokens, keys, options) {
   var strict = options.strict
   var end = options.end !== false
   var route = ''
-  var lastToken = tokens[tokens.length - 1]
-  var endsWithSlash = typeof lastToken === 'string' && /\/$/.test(lastToken)
 
   // Iterate over the tokens and create our regexp string.
   for (var i = 0; i < tokens.length; i++) {
@@ -374,20 +372,23 @@ function tokensToRegExp (tokens, keys, options) {
     }
   }
 
+  var delimiter = escapeString(options.delimiter || '/')
+  var endsWithDelimiter = route.slice(-delimiter.length) === delimiter
+
   // In non-strict mode we allow a slash at the end of match. If the path to
   // match already ends with a slash, we remove it for consistency. The slash
   // is valid at the end of a path match, not in the middle. This is important
   // in non-ending mode, where "/test/" shouldn't match "/test//route".
   if (!strict) {
-    route = (endsWithSlash ? route.slice(0, -2) : route) + '(?:\\/(?=$))?'
+    route = (endsWithDelimiter ? route.slice(0, -delimiter.length) : route) + '(?:' + delimiter + '(?=$))?'
   }
 
   if (end) {
     route += '$'
   } else {
     // In non-ending mode, we need the capturing groups to match as much as
     // possible by using a positive lookahead to the end or next path segment.
-    route += strict && endsWithSlash ? '' : '(?=\\/|$)'
+    route += strict && endsWithDelimiter ? '' : '(?=' + delimiter + '|$)'
   }
 
   return attachKeys(new RegExp('^' + route, flags(options)), keys)

test.ts

@@ -2221,6 +2221,23 @@ var TESTS: Test[] = [
       [{ ext: 'com' }, 'example.com'],
       [{ ext: 'org' }, 'example.org']
     ]
+  ],
+  [
+    'this is',
+    {
+      delimiter: ' ',
+      end: false
+    },
+    [
+      'this is'
+    ],
+    [
+      ['this is a test', ['this is']],
+      ['this isn\'t', null]
+    ],
+    [
+      [null, 'this is']
+    ]
   ]
 ]