fix(common): capitalize first letter of all words in TitleCasePipe (#13511)

modules/@angular/common/src/pipes/case_conversion_pipes.ts

@@ -27,6 +27,17 @@ export class LowerCasePipe implements PipeTransform {
   }
 }
 
+
+/**
+ * Helper method to transform a single word to titlecase.
+ *
+ * @stable
+ */
+function titleCaseWord(word: string) {
+  if (!word) return word;
+  return word[0].toUpperCase() + word.substr(1).toLowerCase();
+}
+
 /**
  * Transforms text to titlecase.
  *
@@ -40,7 +51,7 @@ export class TitleCasePipe implements PipeTransform {
       throw new InvalidPipeArgumentError(TitleCasePipe, value);
     }
 
-    return value[0].toUpperCase() + value.substr(1).toLowerCase();
+    return value.split(/\b/g).map(word => titleCaseWord(word)).join('');
   }
 }
 

modules/@angular/common/test/pipes/case_conversion_pipes_spec.ts

@@ -32,6 +32,14 @@ export function main() {
 
     it('should return titlecase', () => { expect(pipe.transform('foo')).toEqual('Foo'); });
 
+    it('should return titlecase for subsequent words',
+       () => { expect(pipe.transform('one TWO Three fouR')).toEqual('One Two Three Four'); });
+
+    it('should support empty strings', () => { expect(pipe.transform('')).toEqual(''); });
+
+    it('should persist whitespace',
+       () => { expect(pipe.transform('one   two')).toEqual('One   Two'); });
+
     it('should titlecase when there is a new value', () => {
       expect(pipe.transform('bar')).toEqual('Bar');
       expect(pipe.transform('foo')).toEqual('Foo');