Document magic constants by pulling them into vars and commenting them

Author: papandreou

lib/parse.js

@@ -22,6 +22,19 @@ var interpretNumericEntities = function (str) {
     });
 };
 
+// This is what browsers will submit when the ✓ character occurs in an
+// application/x-www-form-urlencoded body and the encoding of the page containing
+// the form is iso-8859-1, or when the submitted form has an accept-charset
+// attribute of iso-8859-1. Presumably also with other charsets that does no contain
+// the ✓ character, such as us-ascii.
+var numericCheckmark = '✓';
+
+// These are the raw utf-8 bytes of the checkmark as code points in a string.
+// It's what we end up with when the utf-8 sentinel parameter is interpreted
+// as iso-8859-1. When utf8Sentinel is enabled, we will use it to course-correct
+// and interpret the rest of the query string as utf-8.
+var misinterpretedCheckmark = '\xe2\x9c\x93';
+
 var parseValues = function parseQueryStringValues(str, options) {
     var obj = {};
     var cleanStr = options.ignoreQueryPrefix ? str.replace(/^\?/, '') : str;
@@ -43,10 +56,11 @@ var parseValues = function parseQueryStringValues(str, options) {
             key = options.decoder(part.slice(0, pos), defaults.decoder, charset);
             val = options.decoder(part.slice(pos + 1), defaults.decoder, charset);
         }
+
         if (key === 'utf8' && options.utf8Sentinel) {
-            if (val === '✓' || val === '\xe2\x9c\x93') {
+            if (val === '✓' || val === misinterpretedCheckmark) {
                 charset = 'utf-8';
-            } else if (val === '✓') {
+            } else if (val === numericCheckmark) {
                 charset = 'iso-8859-1';
             }
         } else {