Update String#trim spec compliance

Test for incorrect trimming of NEL, trim ZWSP (which *is* trimmable in the oldest Unicode spec ES5 targets), reduce the number of string concatenations, and more quickly determine `hasTrimWhitespaceBug` to be false in the usual pre-ES5 case. I would change `if (typeof this === 'undefined' || this === null)` to `if (this == null)` but I don't know whether that's allowed by this library's style guide.
es-shims · Aug 23, 2015 · ff50a01 · ff50a01
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commit ff50a01
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Showing 2 changed files with 15 additions and 12 deletions.
diff --git a/es5-shim.js b/es5-shim.js
@@ -1519,14 +1519,15 @@ defineProperties(StringPrototype, {
 
 // ES5 15.5.4.20
 // whitespace from: http://es5.github.io/#x15.5.4.20
-var ws = '\x09\x0A\x0B\x0C\x0D\x20\xA0\u1680\u180E\u2000\u2001\u2002\u2003' +
-    '\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000\u2028' +
-    '\u2029\uFEFF';
-var zeroWidth = '\u200b';
-var wsRegexChars = '[' + ws + ']';
-var trimBeginRegexp = new RegExp('^' + wsRegexChars + wsRegexChars + '*');
-var trimEndRegexp = new RegExp(wsRegexChars + wsRegexChars + '*$');
-var hasTrimWhitespaceBug = StringPrototype.trim && (ws.trim() || !zeroWidth.trim());
+var ws = '\t\n\v\f\r \xA0\u1680\u180E\u2000\u2001\u2002\u2003\u2004\u2005' +
+  '\u2006\u2007\u2008\u2009\u200A\u200B\u2028\u2029\u202F\u205F\u3000\uFEFF';
+var nxtLine = '\x85';
+var wsRegexChars = '[' + ws + '][' + ws + ']*';
+var trimBeginRegexp = new RegExp('^' + wsRegexChars);
+var trimEndRegexp = new RegExp(wsRegexChars + '$');
+var hasTrimWhitespaceBug = 'trim' in StringPrototype &&
+  typeof StringPrototype.trim === 'function' &&
+  (ws.trim() !== '' || nxtLine.trim() === '');
 defineProperties(StringPrototype, {
     // http://blog.stevenlevithan.com/archives/faster-trim-javascript
     // http://perfectionkills.com/whitespace-deviations/

diff --git a/tests/spec/s-string.js b/tests/spec/s-string.js
@@ -4,16 +4,18 @@ describe('String', function () {
     'use strict';
 
     describe('trim', function () {
-        var test = '\x09\x0A\x0B\x0C\x0D\x20\xA0\u1680\u180E\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000\u2028\u2029\uFEFFHello, World!\x09\x0A\x0B\x0C\x0D\x20\xA0\u1680\u180E\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u202F\u205F\u3000\u2028\u2029\uFEFF';
+        var wsp = '\t\n\v\f\r \xA0\u1680\u180E\u2000\u2001\u2002\u2003\u2004\u2005' +
+          '\u2006\u2007\u2008\u2009\u200A\u200B\u2028\u2029\u202F\u205F\u3000\uFEFF';
+        var test = [wsp, 'Hello, World!', wsp].join('');
 
         it('trims all ES5 whitespace', function () {
             expect(test.trim()).toEqual('Hello, World!');
             expect(test.trim().length).toBe(13);
         });
 
-        it('does not trim the zero-width space', function () {
-            expect('\u200b'.trim()).toBe('\u200b');
-            expect('\u200b'.trim().length).toBe(1);
+        it('does not trim the next-line character', function () {
+            expect('\x85'.trim()).toBe('\x85');
+            expect('\x85'.trim().length).toBe(1);
         });
     });