feat(forms): handle string with and without line boundary on pattern validator (#19256)

ghetolay · alexeagle · commit 75f8522b8de3 · 2018-01-16T07:12:14.000-08:00
PR Close #19256
diff --git a/packages/forms/src/validators.ts b/packages/forms/src/validators.ts
@@ -163,7 +163,14 @@ export class Validators {
     let regex: RegExp;
     let regexStr: string;
     if (typeof pattern === 'string') {
-      regexStr = `^${pattern}$`;
+      regexStr = '';
+
+      if (pattern.charAt(0) !== '^') regexStr += '^';
+
+      regexStr += pattern;
+
+      if (pattern.charAt(pattern.length - 1) !== '$') regexStr += '$';
+
       regex = new RegExp(regexStr);
     } else {
       regexStr = pattern.toString();
diff --git a/packages/forms/test/validators_spec.ts b/packages/forms/test/validators_spec.ts
@@ -270,6 +270,12 @@ import {map} from 'rxjs/operator/map';
 
       it('should not error on "undefined" pattern',
          () => expect(Validators.pattern(undefined !)(new FormControl('aaAA'))).toBeNull());
+
+      it('should work with string containing line boundary',
+         () => expect(Validators.pattern('^[aA]*$')(new FormControl('aaAA'))).toBeNull());
+
+      it('should work with string not containing line boundary',
+         () => expect(Validators.pattern('[aA]*')(new FormControl('aaAA'))).toBeNull());
     });
 
     describe('compose', () => {
