fix(button): submit form when pressing enter key (#27790)

Issue number: resolves #19368 

---------

<!-- Please do not submit updates to dependencies unless it fixes an
issue. -->

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etc). Submit multiple pull requests if needed. -->

## What is the current behavior?

The form submits when clicking on the `ion-button`. However, users
cannot submit the form when focused on a form element and pressing the
`enter` button. This does not follow the behavior of the native button
on a form.

## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- Form now submits when a form element is focused and the `enter` button
is pressed.
  - It also submits regardless of the amount of form elements present.
- Form will not submit if the `ion-button` is disabled.

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

<!-- If this introduces a breaking change, please describe the impact
and migration path for existing applications below. -->


## Other information

<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->

N/A

core/src/components/button/button.tsx

@@ -1,5 +1,5 @@
 import type { ComponentInterface, EventEmitter } from '@stencil/core';
-import { Component, Element, Event, Host, Prop, h } from '@stencil/core';
+import { Component, Element, Event, Host, Prop, Watch, h } from '@stencil/core';
 import type { AnchorInterface, ButtonInterface } from '@utils/element-interface';
 import type { Attributes } from '@utils/helpers';
 import { inheritAriaAttributes, hasShadowDom } from '@utils/helpers';
@@ -32,6 +32,8 @@ export class Button implements ComponentInterface, AnchorInterface, ButtonInterf
   private inItem = false;
   private inListHeader = false;
   private inToolbar = false;
+  private formButtonEl: HTMLButtonElement | null = null;
+  private formEl: HTMLFormElement | null = null;
   private inheritedAttributes: Attributes = {};
 
   @Element() el!: HTMLElement;
@@ -52,6 +54,13 @@ export class Button implements ComponentInterface, AnchorInterface, ButtonInterf
    * If `true`, the user cannot interact with the button.
    */
   @Prop({ reflect: true }) disabled = false;
+  @Watch('disabled')
+  disabledChanged() {
+    const { disabled } = this;
+    if (this.formButtonEl) {
+      this.formButtonEl.disabled = disabled;
+    }
+  }
 
   /**
    * Set to `"block"` for a full-width button or to `"full"` for a full-width button
@@ -144,6 +153,22 @@ export class Button implements ComponentInterface, AnchorInterface, ButtonInterf
    */
   @Event() ionBlur!: EventEmitter<void>;
 
+  connectedCallback(): void {
+    // Allow form to be submitted through `ion-button`
+    if (this.type !== 'button' && hasShadowDom(this.el)) {
+      this.formEl = this.findForm();
+      if (this.formEl) {
+        // Create a hidden native button inside of the form
+        this.formButtonEl = document.createElement('button');
+        this.formButtonEl.type = this.type;
+        this.formButtonEl.style.display = 'none';
+        // Only submit if the button is not disabled.
+        this.formButtonEl.disabled = this.disabled;
+        this.formEl.appendChild(this.formButtonEl);
+      }
+    }
+  }
+
   componentWillLoad() {
     this.inToolbar = !!this.el.closest('ion-buttons');
     this.inListHeader = !!this.el.closest('ion-list-header');
@@ -177,62 +202,71 @@ export class Button implements ComponentInterface, AnchorInterface, ButtonInterf
       return form;
     }
     if (typeof form === 'string') {
-      const el = document.getElementById(form);
+      // Check if the string provided is a form id.
+      const el: HTMLElement | null = document.getElementById(form);
+      if (el) {
         if (el instanceof HTMLFormElement) {
           return el;
-      }
+        } else {
-    }
+          /**
+           * The developer specified a string for the form attribute, but the
+           * element with that id is not a form element.
+           */
+          printIonWarning(
+            `Form with selector: "#${form}" could not be found. Verify that the id is attached to a <form> element.`,
+            this.el
+          );
           return null;
         }
+      } else {
+        /**
+         * The developer specified a string for the form attribute, but the
+         * element with that id could not be found in the DOM.
+         */
+        printIonWarning(
+          `Form with selector: "#${form}" could not be found. Verify that the id is correct and the form is rendered in the DOM.`,
+          this.el
+        );
+        return null;
+      }
+    }
+    if (form !== undefined) {
+      /**
+       * The developer specified a HTMLElement for the form attribute,
+       * but the element is not a HTMLFormElement.
+       * This will also catch if the developer tries to pass in null
+       * as the form attribute.
+       */
+      printIonWarning(
+        `The provided "form" element is invalid. Verify that the form is a HTMLFormElement and rendered in the DOM.`,
+        this.el
+      );
+      return null;
+    }
+    /**
+     * If the form element is not set, the button may be inside
+     * of a form element. Query the closest form element to the button.
+     */
+    return this.el.closest('form');
+  }
+
+  private submitForm(ev: Event) {
+    // this button wants to specifically submit a form
+    // climb up the dom to see if we're in a <form>
+    // and if so, then use JS to submit it
+    if (this.formEl && this.formButtonEl) {
+      ev.preventDefault();
+
+      this.formButtonEl.click();
+    }
+  }
 
   private handleClick = (ev: Event) => {
     const { el } = this;
     if (this.type === 'button') {
       openURL(this.href, ev, this.routerDirection, this.routerAnimation);
     } else if (hasShadowDom(el)) {
-      // this button wants to specifically submit a form
+      this.submitForm(ev);
-      // climb up the dom to see if we're in a <form>
-      // and if so, then use JS to submit it
-      let formEl = this.findForm();
-      const { form } = this;
-
-      if (!formEl && form !== undefined) {
-        /**
-         * The developer specified a form selector for
-         * the button to submit, but it was not found.
-         */
-        if (typeof form === 'string') {
-          printIonWarning(
-            `Form with selector: "#${form}" could not be found. Verify that the id is correct and the form is rendered in the DOM.`,
-            el
-          );
-        } else {
-          printIonWarning(
-            `The provided "form" element is invalid. Verify that the form is a HTMLFormElement and rendered in the DOM.`,
-            el
-          );
-        }
-        return;
-      }
-
-      if (!formEl) {
-        /**
-         * If the form element is not set, the button may be inside
-         * of a form element. Query the closest form element to the button.
-         */
-        formEl = el.closest('form');
-      }
-
-      if (formEl) {
-        ev.preventDefault();
-
-        const fakeButton = document.createElement('button');
-        fakeButton.type = this.type;
-        fakeButton.style.display = 'none';
-        formEl.appendChild(fakeButton);
-        fakeButton.click();
-        fakeButton.remove();
-      }
     }
   };
 

core/src/components/button/test/form-reference/button.e2e.ts

@@ -56,19 +56,93 @@ configs({ directions: ['ltr'], modes: ['ios'] }).forEach(({ title, config }) =>
 
       expect(submitEvent).toHaveReceivedEvent();
     });
+
+    test('should submit the closest form by pressing the `enter` button on a form element', async ({
+      page,
+    }, testInfo) => {
+      testInfo.annotations.push({
+        type: 'issue',
+        description: 'https://github.com/ionic-team/ionic-framework/issues/19368',
+      });
+
+      await page.setContent(
+        `
+        <form>
+          <input type="text" />
+          <ion-button type="submit">Submit</ion-button>
+        </form>
+      `,
+        config
+      );
+
+      const submitEvent = await page.spyOnEvent('submit');
+
+      await page.press('input', 'Enter');
+
+      expect(submitEvent).toHaveReceivedEvent();
+    });
+
+    test('should submit the closest form with multiple elements by pressing the `enter` button', async ({
+      page,
+    }, testInfo) => {
+      testInfo.annotations.push({
+        type: 'issue',
+        description: 'https://github.com/ionic-team/ionic-framework/issues/19368',
+      });
+
+      await page.setContent(
+        `
+        <form>
+          <input type="text" />
+          <textarea></textarea>
+          <ion-button type="submit">Submit</ion-button>
+        </form>
+      `,
+        config
+      );
+
+      const submitEvent = await page.spyOnEvent('submit');
+
+      await page.press('input', 'Enter');
+
+      expect(submitEvent).toHaveReceivedEvent();
+    });
+
+    test('should not submit the closest form when button is disabled', async ({ page }, testInfo) => {
+      testInfo.annotations.push({
+        type: 'issue',
+        description: 'https://github.com/ionic-team/ionic-framework/issues/19368',
+      });
+
+      await page.setContent(
+        `
+        <form>
+          <input type="text" />
+          <ion-button type="submit" disabled>Submit</ion-button>
+        </form>
+      `,
+        config
+      );
+
+      const submitEvent = await page.spyOnEvent('submit');
+
+      await page.press('input', 'Enter');
+
+      expect(submitEvent).not.toHaveReceivedEvent();
+    });
   });
 
   test.describe(title('should throw a warning if the form cannot be found'), () => {
     test('form is a string selector', async ({ page }) => {
-      await page.setContent(`<ion-button type="submit" form="missingForm">Submit</ion-button>`, config);
-
       const logs: string[] = [];
 
       page.on('console', (msg) => {
+        if (msg.type() === 'warning') {
           logs.push(msg.text());
+        }
       });
 
-      await page.click('ion-button');
+      await page.setContent(`<ion-button type="submit" form="missingForm">Submit</ion-button>`, config);
 
       expect(logs.length).toBe(1);
       expect(logs[0]).toContain(
@@ -77,6 +151,14 @@ configs({ directions: ['ltr'], modes: ['ios'] }).forEach(({ title, config }) =>
     });
 
     test('form is an element reference', async ({ page }) => {
+      const logs: string[] = [];
+
+      page.on('console', (msg) => {
+        if (msg.type() === 'warning') {
+          logs.push(msg.text());
+        }
+      });
+
       await page.setContent(
         `
         <ion-button type="submit">Submit</ion-button>
@@ -90,14 +172,6 @@ configs({ directions: ['ltr'], modes: ['ios'] }).forEach(({ title, config }) =>
         config
       );
 
-      const logs: string[] = [];
-
-      page.on('console', (msg) => {
-        logs.push(msg.text());
-      });
-
-      await page.click('ion-button');
-
       expect(logs.length).toBe(1);
       expect(logs[0]).toContain(
         '[Ionic Warning]: The provided "form" element is invalid. Verify that the form is a HTMLFormElement and rendered in the DOM.'