Handle leading and embedded quotes

Fixes #15

README.md

@@ -78,13 +78,23 @@ test('Capitalize words with cyrillic characters', function (t) {
 })
 ```
 
-and thanks to [@ultraflynn](https://github.com/grncdr/js-capitalize/pull/3), capitalize properly handles quotes within the string:
+and thanks to [@ultraflynn](https://github.com/grncdr/js-capitalize/pull/3) and [@DatGuyJonathon](https://github.com/grncdr/js-capitalize/issues/15) capitalize properly handles quotes within the string:
 
 ```javascript
 test('Capitalize each word, ignoring quotes', function(t) {
     t.plan(1)
     t.equal(capitalize.words("it's a nice day"), "It's A Nice Day")
 })
+
+test('Quotes test case 2', function(t) {
+    t.plan(1)
+    t.equal(capitalize.words("It’s a Boy"), "It’s A Boy")
+})
+
+test('Handles embedded quotes', function(t) {
+    t.plan(1)
+    t.equal(capitalize.words("'There's angels among us'"), "'There's Angels Among Us'")
+})
 ```
 
 and thanks to [@sergejkaravajnij](https://github.com/grncdr/js-capitalize/pull/9), capitalize also supports a second boolean parameter to preserve casing of the rest of the strings content:

index.js

@@ -7,22 +7,38 @@ function capitalize (string, opts) {
   return string.charAt(0).toUpperCase() + string.substring(1);
 }
 
+// a QUOTE character immediately followed by a word character
+var QUOTE = /['"`’]/
+var WORD = /[0-9a-zA-Z\u00C0-\u017F\u0400-\u04FF]/
+
 capitalize.words = function (string, opts) {
   opts = normalizeOptions(opts)
   if (!opts.preserve) {
     string = string.toLowerCase();
   }
-  var start = 0
-  var nonWord = /[^0-9a-zA-Z\u00C0-\u017F\u0400-\u04FF']+|$/g
+  var startOfWord = 0
+  var nonWord = /[^0-9a-zA-Z\u00C0-\u017F\u0400-\u04FF]+|$/g
   var match
   var out = ""
 
   while (match = nonWord.exec(string)) {
-    var suffix = match[0]
-    var word = string.substring(start, nonWord.lastIndex - suffix.length)
-    out += capitalize(word, opts) + suffix
-    start = nonWord.lastIndex
-    if (start == string.length) break
+    var sep = match[0]
+    var sepStart = nonWord.lastIndex - sep.length
+    if (QUOTE.test(string[sepStart]) && WORD.test(string[sepStart + 1])) {
+      // don't capitalize after an embedded quote
+      continue
+    }
+    var word = string.substring(startOfWord, nonWord.lastIndex - sep.length)
+    if (QUOTE.test(word[0])) {
+      // strip leading quote
+      out += word[0]
+      word = word.substring(1)
+    }
+    out += capitalize(word, opts) + sep
+    startOfWord = nonWord.lastIndex
+    if (startOfWord == string.length) {
+      break
+    }
   }
 
   return out