Address comments

src/lib/core/core.ts

@@ -120,7 +120,7 @@ export {
 
 // Error
 export {
-  ErrorStateMatcherType,
+  ErrorStateMatcher,
   ErrorOptions,
   MD_ERROR_GLOBAL_OPTIONS
 } from './error/error-options';

src/lib/core/error/error-options.ts

@@ -1,14 +1,45 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
 import {InjectionToken} from '@angular/core';
 import {NgControl, FormGroupDirective, NgForm} from '@angular/forms';
 
 /** Injection token that can be used to specify the global error options. */
 export const MD_ERROR_GLOBAL_OPTIONS =
-  new InjectionToken<() => boolean>('md-error-global-options');
+  new InjectionToken<ErrorOptions>('md-error-global-options');
 
-export type ErrorStateMatcherType =
+export type ErrorStateMatcher =
   (control: NgControl, parentFormGroup: FormGroupDirective, parentForm: NgForm) => boolean;
 
 export interface ErrorOptions {
-  errorStateMatcher?: ErrorStateMatcherType;
-  showOnDirty?: boolean;
+  errorStateMatcher?: ErrorStateMatcher;
+}
+
+export class DefaultErrorStateMatcher {
+
+  errorStateMatcher(control: NgControl, formGroup: FormGroupDirective, form: NgForm): boolean {
+    const isInvalid = control && control.invalid;
+    const isTouched = control && control.touched;
+    const isSubmitted = (formGroup && formGroup.submitted) ||
+        (form && form.submitted);
+
+    return !!(isInvalid && (isTouched || isSubmitted));
+  }
+}
+
+export class ShowOnDirtyErrorStateMatcher {
+
+  errorStateMatcher(control: NgControl, formGroup: FormGroupDirective, form: NgForm): boolean {
+    const isInvalid = control && control.invalid;
+    const isDirty = control && control.dirty;
+    const isSubmitted = (formGroup && formGroup.submitted) ||
+        (form && form.submitted);
+
+    return !!(isInvalid && (isDirty || isSubmitted));
+  }
 }

src/lib/input/input-container.spec.ts

@@ -24,7 +24,7 @@ import {
   getMdInputContainerPlaceholderConflictError
 } from './input-container-errors';
 import {MD_PLACEHOLDER_GLOBAL_OPTIONS} from '../core/placeholder/placeholder-options';
-import {MD_ERROR_GLOBAL_OPTIONS} from '../core/error/error-options';
+import {MD_ERROR_GLOBAL_OPTIONS, ShowOnDirtyErrorStateMatcher} from '../core/error/error-options';
 
 describe('MdInputContainer', function () {
   beforeEach(async(() => {
@@ -676,8 +676,6 @@ describe('MdInputContainer', function () {
     }));
 
     it('should display an error message when the parent form group is submitted', async(() => {
-      fixture.destroy();
-
       let groupFixture = TestBed.createComponent(MdInputContainerWithFormGroupErrorMessages);
       let component: MdInputContainerWithFormGroupErrorMessages;
 
@@ -709,8 +707,6 @@ describe('MdInputContainer', function () {
     }));
 
     it('should display an error message when a custom error matcher returns true', async(() => {
-      fixture.destroy();
-
       let customFixture = TestBed.createComponent(MdInputContainerWithCustomErrorStateMatcher);
       let component: MdInputContainerWithCustomErrorStateMatcher;
 
@@ -726,14 +722,14 @@ describe('MdInputContainer', function () {
 
       customFixture.whenStable().then(() => {
         expect(containerEl.querySelectorAll('md-error').length)
-          .toBe(0, 'Expected no error messages after being touched.');
+            .toBe(0, 'Expected no error messages after being touched.');
 
         component.errorState = true;
         customFixture.detectChanges();
 
         customFixture.whenStable().then(() => {
           expect(containerEl.querySelectorAll('md-error').length)
-            .toBe(1, 'Expected one error messages to have been rendered.');
+              .toBe(1, 'Expected one error messages to have been rendered.');
         });
       });
     }));
@@ -774,7 +770,7 @@ describe('MdInputContainer', function () {
       expect(containerEl.querySelectorAll('md-error').length).toBe(1, 'Expected an error message');
     });
 
-    it('should display an error message when global setting shows errors on dirty', async() => {
+    it('should display an error message when using ShowOnDirtyErrorStateMatcher', async(() => {
       TestBed.resetTestingModule();
       TestBed.configureTestingModule({
         imports: [
@@ -787,7 +783,7 @@ describe('MdInputContainer', function () {
           MdInputContainerWithFormErrorMessages
         ],
         providers: [
-          { provide: MD_ERROR_GLOBAL_OPTIONS, useValue: { showOnDirty: true } }
+          { provide: MD_ERROR_GLOBAL_OPTIONS, useClass: ShowOnDirtyErrorStateMatcher }
         ]
       });
 
@@ -805,18 +801,18 @@ describe('MdInputContainer', function () {
 
       customFixture.whenStable().then(() => {
         expect(containerEl.querySelectorAll('md-error').length)
-          .toBe(0, 'Expected no error messages when touched');
+            .toBe(0, 'Expected no error messages when touched');
 
         testComponent.formControl.markAsDirty();
         customFixture.detectChanges();
 
         customFixture.whenStable().then(() => {
           expect(containerEl.querySelectorAll('md-error').length)
-            .toBe(1, 'Expected one error message when dirty');
+              .toBe(1, 'Expected one error message when dirty');
         });
       });
 
-    });
+    }));
 
     it('should hide the errors and show the hints once the input becomes valid', async(() => {
       testComponent.formControl.markAsTouched();

src/lib/input/input-container.ts

@@ -43,7 +43,8 @@ import {
   MD_PLACEHOLDER_GLOBAL_OPTIONS
 } from '../core/placeholder/placeholder-options';
 import {
-  ErrorStateMatcherType,
+  DefaultErrorStateMatcher,
+  ErrorStateMatcher,
   ErrorOptions,
   MD_ERROR_GLOBAL_OPTIONS
 } from '../core/error/error-options';
@@ -196,7 +197,7 @@ export class MdInputDirective {
   }
 
   /** A function used to control when error messages are shown. */
-  @Input() errorStateMatcher: ErrorStateMatcherType;
+  @Input() errorStateMatcher: ErrorStateMatcher;
 
   /** The input element's value. */
   get value() { return this._elementRef.nativeElement.value; }
@@ -240,7 +241,8 @@ export class MdInputDirective {
     this.id = this.id;
 
     this._errorOptions = errorOptions ? errorOptions : {};
-    this.errorStateMatcher = this._errorOptions.errorStateMatcher || undefined;
+    this.errorStateMatcher = this._errorOptions.errorStateMatcher
+        || new DefaultErrorStateMatcher().errorStateMatcher;
   }
 
   /** Focuses the input element. */
@@ -263,24 +265,7 @@ export class MdInputDirective {
   /** Whether the input is in an error state. */
   _isErrorState(): boolean {
     const control = this._ngControl;
-    return this.errorStateMatcher
-      ? this.errorStateMatcher(control, this._parentFormGroup, this._parentForm)
-      : this._defaultErrorStateMatcher(control);
-  }
-
-  /** Default error state calculation */
-  private _defaultErrorStateMatcher(control: NgControl): boolean {
-    const isInvalid = control && control.invalid;
-    const isTouched = control && control.touched;
-    const isDirty = control && control.dirty;
-    const isSubmitted = (this._parentFormGroup && this._parentFormGroup.submitted) ||
-        (this._parentForm && this._parentForm.submitted);
-
-    if (this._errorOptions.showOnDirty) {
-      return !!(isInvalid && (isDirty || isSubmitted));
-    }
-
-    return !!(isInvalid && (isTouched || isSubmitted));
+    return this.errorStateMatcher(control, this._parentFormGroup, this._parentForm);
   }
 
   /** Make sure the input is a supported type. */

src/lib/input/input.md

@@ -142,8 +142,17 @@ to all inputs.
 
 Here are the available global options:
 
-
 | Name              | Type     | Description |
 | ----------------- | -------- | ----------- |
 | errorStateMatcher | Function | Returns a boolean specifying if the error should be shown |
-| showOnDirty       | boolean  | If true, the error will show when the control is dirty, not touched. |P
+
+
+If you just wish to make all inputs behave the same as the default, but show errors when
+dirty instead of touched, you can use the `ShowOnDirtyErrorStateMatcher` implementation.
+
+```ts
+@NgModule({
+  providers: [
+    { provide: MD_ERROR_GLOBAL_OPTIONS, useClass: ShowOnDirtyErrorStateMatcher }
+  ]
+})