Add support for reset button

Part of #117, this adds support for resetting the state of the form using a native reset button. Yielding a `reset` action will come in a separate PR.

packages/ember-headless-form/src/components/headless-form.gts

@@ -462,6 +462,18 @@ export default class HeadlessFormComponent<
     }
   }
 
+  @action
+  async onReset(e: Event): Promise<void> {
+    e.preventDefault();
+
+    for (const key of Object.keys(this.internalData)) {
+      delete this.internalData[key as keyof DATA];
+    }
+
+    this.validationState = undefined;
+    this.submissionState = undefined;
+  }
+
   @action
   registerField(
     name: FormKey<FormData<DATA>>,
@@ -562,6 +574,7 @@ export default class HeadlessFormComponent<
       ...attributes
       {{this.registerForm}}
       {{on "submit" this.onSubmit}}
+      {{on "reset" this.onReset}}
       {{this.onValidation this.fieldValidationEvent this.handleFieldValidation}}
       {{this.onValidation
         this.fieldRevalidationEvent

test-app/app/templates/index.hbs

@@ -103,4 +103,9 @@
     class='bg-slate-600 text-white rounded px-8 py-1'
     data-test-submit
   >Submit</button>
+  <button
+    type='reset'
+    class='bg-slate-400 text-white rounded px-8 py-1'
+    data-test-reset
+  >Reset</button>
 </HeadlessForm>

test-app/tests/integration/components/headless-form-reset-test.gts

@@ -0,0 +1,156 @@
+/* eslint-disable no-undef -- Until https://github.com/ember-cli/eslint-plugin-ember/issues/1747 is resolved... */
+/* eslint-disable simple-import-sort/imports,padding-line-between-statements,decorator-position/decorator-position -- Can't fix these manually, without --fix working in .gts */
+
+import { click, fillIn, render } from '@ember/test-helpers';
+import { module, test } from 'qunit';
+
+import { HeadlessForm } from 'ember-headless-form';
+import { setupRenderingTest } from 'test-app/tests/helpers';
+
+interface TestFormData {
+  firstName?: string;
+  lastName?: string;
+}
+
+module('Integration Component HeadlessForm > Reset', function (hooks) {
+  setupRenderingTest(hooks);
+
+  module('reset button', function () {
+    test('dirty fields are resetted', async function (assert) {
+      const data: TestFormData = { firstName: 'Tony', lastName: 'Ward' };
+
+      await render(<template>
+        <HeadlessForm @data={{data}} as |form|>
+          <form.Field @name="firstName" as |field|>
+            <field.Label>First Name</field.Label>
+            <field.Input data-test-first-name />
+          </form.Field>
+          <form.Field @name="lastName" as |field|>
+            <field.Label>Last Name</field.Label>
+            <field.Input data-test-last-name />
+          </form.Field>
+          <button type="reset" data-test-reset>Reset</button>
+        </HeadlessForm>
+      </template>);
+
+      await fillIn('[data-test-first-name]', 'Nicole');
+      await click('[data-test-reset');
+
+      assert.dom('[data-test-first-name]').hasValue('Tony');
+      assert.dom('[data-test-last-name]').hasValue('Ward');
+    });
+
+    test('validation errors are cleared', async function (assert) {
+      const data: TestFormData = {};
+
+      await render(<template>
+        <HeadlessForm @data={{data}} as |form|>
+          <form.Field @name="firstName" as |field|>
+            <field.Label>First Name</field.Label>
+            <field.Input required data-test-first-name />
+            <field.Errors data-test-first-name-errors />
+            {{#if field.isInvalid}}
+              <div data-test-invalid />
+            {{/if}}
+          </form.Field>
+          <form.Field @name="lastName" as |field|>
+            <field.Label>Last Name</field.Label>
+            <field.Input data-test-last-name />
+            <field.Errors data-test-last-name-errors />
+          </form.Field>
+          <button type="submit" data-test-submit>Submit</button>
+          <button type="reset" data-test-reset>Reset</button>
+        </HeadlessForm>
+      </template>);
+
+      await click('[data-test-submit]');
+
+      assert
+        .dom('[data-test-first-name-errors]')
+        .exists({ count: 1 }, 'validation errors appear when validation fails');
+      assert.dom('[data-test-first-name]').hasAria('invalid', 'true');
+      assert.dom('[data-test-invalid]').exists();
+
+      await click('[data-test-reset]');
+
+      assert
+        .dom('[data-test-first-name-errors]')
+        .doesNotExist('validation errors are removed on reset');
+      assert.dom('[data-test-first-name]').doesNotHaveAria('invalid');
+      assert.dom('[data-test-invalid]').doesNotExist();
+    });
+
+    test('validation state is resetted', async function (assert) {
+      const data: TestFormData = {};
+
+      await render(<template>
+        <HeadlessForm @data={{data}} as |form|>
+          <form.Field @name="firstName" as |field|>
+            <field.Label>First Name</field.Label>
+            <field.Input required data-test-first-name />
+          </form.Field>
+          <button type="submit" data-test-submit>Submit</button>
+          <button type="reset" data-test-reset>Reset</button>
+          {{#if form.validationState}}
+            <div data-test-validation-state>{{form.validationState.state}}</div>
+          {{/if}}
+        </HeadlessForm>
+      </template>);
+
+      assert
+        .dom('[data-test-validation-state]')
+        .doesNotExist(
+          'form.validationState is not present until first validation'
+        );
+
+      await click('[data-test-submit]');
+
+      assert
+        .dom('[data-test-validation-state]')
+        .hasText('RESOLVED', 'form.validationState has resolved');
+
+      await click('[data-test-reset]');
+
+      assert
+        .dom('[data-test-validation-state]')
+        .doesNotExist('form.validationState is resetted');
+    });
+
+    test('submission state is resetted', async function (assert) {
+      const data: TestFormData = {};
+      const submitHandler = () => 'ok';
+
+      await render(<template>
+        <HeadlessForm @data={{data}} @onSubmit={{submitHandler}} as |form|>
+          <form.Field @name="firstName" as |field|>
+            <field.Label>First Name</field.Label>
+            <field.Input data-test-first-name />
+          </form.Field>
+          <button type="submit" data-test-submit>Submit</button>
+          <button type="reset" data-test-reset>Reset</button>
+          {{#if form.submissionState}}
+            <div data-test-submission-state>{{form.submissionState.state}}</div>
+          {{/if}}
+        </HeadlessForm>
+      </template>);
+
+      assert
+        .dom('[data-test-submission-state]')
+        .doesNotExist(
+          'form.submissionState is not present until first validation'
+        );
+
+      await click('[data-test-submit]');
+
+      assert
+        .dom('[data-test-submission-state]')
+        .hasText('RESOLVED', 'form.submissionState has resolved');
+
+      await click('[data-test-reset]');
+
+      assert
+        .dom('[data-test-submission-state]')
+        .doesNotExist('form.submissionState is resetted');
+    });
+  });
+});