fix(forms): minLength validator treats zero value as zero length (ang…

…ular#23749)
csmehta · Aug 26, 2018 · 408e248 · 408e248
1 parent 8fa0991
commit 408e248
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Showing 2 changed files with 21 additions and 2 deletions.
diff --git a/packages/forms/src/validators.ts b/packages/forms/src/validators.ts
@@ -228,7 +228,8 @@ export class Validators {
       if (isEmptyInputValue(control.value)) {
         return null;  // don't validate empty values to allow optional controls
       }
-      const length: number = control.value ? control.value.length : 0;
+
+      const length: number = (Validators.getLength(control.value));
       return length < minLength ?
           {'minlength': {'requiredLength': minLength, 'actualLength': length}} :
           null;
@@ -260,13 +261,22 @@ export class Validators {
    */
   static maxLength(maxLength: number): ValidatorFn {
     return (control: AbstractControl): ValidationErrors | null => {
-      const length: number = control.value ? control.value.length : 0;
+      const length: number = (Validators.getLength(control.value));
       return length > maxLength ?
           {'maxlength': {'requiredLength': maxLength, 'actualLength': length}} :
           null;
     };
   }
 
+  private static getLength(value: any): number {
+    if (value.hasOwnProperty('length'))
+      return value.length;
+    else if (value.__proto__.hasOwnProperty('toString')) {
+      return value.toString().length;
+    }
+    return 0;
+  }
+
   /**
    * @description
    * Validator that requires the control's value to match a regex pattern. This validator is also

diff --git a/packages/forms/test/validators_spec.ts b/packages/forms/test/validators_spec.ts
@@ -188,6 +188,15 @@ import {first, map} from 'rxjs/operators';
         });
       });
 
+      it('should not error when valid strings is the number 0',
+         () => { expect(Validators.minLength(1)(new FormControl(0))).toBeNull(); });
+
+      it('should error on short strings with value as the number 0', () => {
+        expect(Validators.minLength(2)(new FormControl(0))).toEqual({
+          'minlength': {'requiredLength': 2, 'actualLength': 1}
+        });
+      });
+
       it('should not error when FormArray has valid length', () => {
         const fa = new FormArray([new FormControl(''), new FormControl('')]);
         expect(Validators.minLength(2)(fa)).toBeNull();