From 7a4d1932ac4b7b649c6cb6fce91b53acf90acb14 Mon Sep 17 00:00:00 2001
From: LucasArray <29403436+LucasArray@users.noreply.github.com>
Date: Fri, 26 Jun 2026 11:42:55 -0400
Subject: [PATCH] fix(fab-button): type="submit" and type="reset" now work
 inside forms

Shadow DOM prevents ion-fab-button's native button from participating
in form submission. Port the hidden-button pattern from ion-button:
inject a hidden <button> into the associated form (found via the new
`form` prop or by walking up to the closest <form> ancestor), then
click it on Host click to trigger native form submission and Enter-key
support.

Fixes #18550
---
 core/src/components/fab-button/fab-button.tsx | 103 +++++++++++--
 .../fab-button/test/form/fab-button.e2e.ts    | 140 ++++++++++++++++++
 .../fab-button/test/form/fab-button.spec.ts   |  31 ++++
 .../fab-button/test/form/index.html           |  66 +++++++++
 4 files changed, 330 insertions(+), 10 deletions(-)
 create mode 100644 core/src/components/fab-button/test/form/fab-button.e2e.ts
 create mode 100644 core/src/components/fab-button/test/form/fab-button.spec.ts
 create mode 100644 core/src/components/fab-button/test/form/index.html

diff --git a/core/src/components/fab-button/fab-button.tsx b/core/src/components/fab-button/fab-button.tsx
index 2a7a4a6198a..2fe225aa2e9 100755
--- a/core/src/components/fab-button/fab-button.tsx
+++ b/core/src/components/fab-button/fab-button.tsx
@@ -1,8 +1,9 @@
 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 { inheritAriaAttributes } from '@utils/helpers';
+import { inheritAriaAttributes, hasShadowDom } from '@utils/helpers';
 import type { Attributes } from '@utils/helpers';
+import { printIonWarning } from '@utils/logging';
 import { createColorClasses, hostContext, openURL } from '@utils/theme';
 import { close } from 'ionicons/icons';
 
@@ -26,6 +27,8 @@ import type { RouterDirection } from '../router/utils/interface';
 })
 export class FabButton implements ComponentInterface, AnchorInterface, ButtonInterface {
   private fab: HTMLIonFabElement | null = null;
+  private formButtonEl: HTMLButtonElement | null = null;
+  private formEl: HTMLFormElement | null = null;
   private inheritedAttributes: Attributes = {};
 
   @Element() el!: HTMLElement;
@@ -46,6 +49,13 @@ export class FabButton implements ComponentInterface, AnchorInterface, ButtonInt
    * If `true`, the user cannot interact with the fab button.
    */
   @Prop() disabled = false;
+  @Watch('disabled')
+  disabledChanged() {
+    const { disabled } = this;
+    if (this.formButtonEl) {
+      this.formButtonEl.disabled = disabled;
+    }
+  }
 
   /**
    * This attribute instructs browsers to download a URL instead of navigating to
@@ -103,6 +113,11 @@ export class FabButton implements ComponentInterface, AnchorInterface, ButtonInt
    */
   @Prop() type: 'submit' | 'reset' | 'button' = 'button';
 
+  /**
+   * The HTML form element or form element id. Used to submit a form when the button is not a child of the form.
+   */
+  @Prop() form?: string | HTMLFormElement;
+
   /**
    * The size of the button. Set this to `small` in order to have a mini fab button.
    */
@@ -137,27 +152,91 @@ export class FabButton implements ComponentInterface, AnchorInterface, ButtonInt
     this.ionBlur.emit();
   };
 
-  private onClick = () => {
-    const { fab } = this;
-    if (!fab) {
-      return;
+  private onClick = (ev: Event) => {
+    const { el, fab } = this;
+    if (this.type !== 'button' && hasShadowDom(el)) {
+      this.submitForm(ev);
+    }
+    if (fab) {
+      fab.toggle();
     }
-
-    fab.toggle();
   };
 
+  /**
+   * Renders a hidden native button inside the associated form so that pressing
+   * Enter on a form field or clicking this component triggers form submission.
+   * The shadow DOM button does not participate in form submission natively,
+   * which is why this workaround is necessary.
+   */
+  private renderHiddenButton() {
+    const formEl = (this.formEl = this.findForm());
+    if (formEl) {
+      const { formButtonEl } = this;
+      if (formButtonEl !== null && formEl.contains(formButtonEl)) {
+        return;
+      }
+      const newFormButtonEl = (this.formButtonEl = document.createElement('button'));
+      newFormButtonEl.type = this.type;
+      newFormButtonEl.style.display = 'none';
+      newFormButtonEl.disabled = this.disabled;
+      formEl.appendChild(newFormButtonEl);
+    }
+  }
+
+  private findForm(): HTMLFormElement | null {
+    const { form } = this;
+    if (form instanceof HTMLFormElement) {
+      return form;
+    }
+    if (typeof form === 'string') {
+      const el: HTMLElement | null = document.getElementById(form);
+      if (el) {
+        if (el instanceof HTMLFormElement) {
+          return el;
+        } else {
+          printIonWarning(
+            `[ion-fab-button] - Form with selector: "#${form}" could not be found. Verify that the id is attached to a <form> element.`,
+            this.el
+          );
+          return null;
+        }
+      } else {
+        printIonWarning(
+          `[ion-fab-button] - Form with selector: "#${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) {
+      printIonWarning(
+        `[ion-fab-button] - The provided "form" element is invalid. Verify that the form is a HTMLFormElement and rendered in the DOM.`,
+        this.el
+      );
+      return null;
+    }
+    return this.el.closest('form');
+  }
+
+  private submitForm(ev: Event) {
+    if (this.formEl && this.formButtonEl) {
+      ev.preventDefault();
+      this.formButtonEl.click();
+    }
+  }
+
   componentWillLoad() {
     this.inheritedAttributes = inheritAriaAttributes(this.el);
   }
 
   render() {
-    const { el, disabled, color, href, activated, show, translucent, size, inheritedAttributes } = this;
+    const { el, disabled, color, href, activated, show, translucent, size, inheritedAttributes, type } = this;
     const inList = hostContext('ion-fab-list', el);
     const mode = getIonMode(this);
     const TagType = href === undefined ? 'button' : ('a' as any);
     const attrs =
       TagType === 'button'
-        ? { type: this.type }
+        ? { type }
         : {
             download: this.download,
             href,
@@ -165,6 +244,10 @@ export class FabButton implements ComponentInterface, AnchorInterface, ButtonInt
             target: this.target,
           };
 
+    if (type !== 'button') {
+      this.renderHiddenButton();
+    }
+
     return (
       <Host
         onClick={this.onClick}
diff --git a/core/src/components/fab-button/test/form/fab-button.e2e.ts b/core/src/components/fab-button/test/form/fab-button.e2e.ts
new file mode 100644
index 00000000000..99a6c8eaa62
--- /dev/null
+++ b/core/src/components/fab-button/test/form/fab-button.e2e.ts
@@ -0,0 +1,140 @@
+import { expect } from '@playwright/test';
+import { configs, test } from '@utils/test/playwright';
+
+configs({ directions: ['ltr'], modes: ['ios'] }).forEach(({ title, config }) => {
+  test.describe(title('fab-button: form'), () => {
+    test('should submit the closest form', async ({ page }) => {
+      await page.setContent(
+        `
+        <form>
+          <ion-fab-button type="submit">Submit</ion-fab-button>
+        </form>
+      `,
+        config
+      );
+
+      const submitEvent = await page.spyOnEvent('submit');
+
+      await page.click('ion-fab-button');
+
+      expect(submitEvent).toHaveReceivedEvent();
+    });
+
+    test('should submit the form by id', async ({ page }) => {
+      await page.setContent(
+        `
+        <form id="myForm"></form>
+        <ion-fab-button form="myForm" type="submit">Submit</ion-fab-button>
+      `,
+        config
+      );
+
+      const submitEvent = await page.spyOnEvent('submit');
+
+      await page.click('ion-fab-button');
+
+      expect(submitEvent).toHaveReceivedEvent();
+    });
+
+    test('should submit the form by reference', async ({ page }) => {
+      await page.setContent(
+        `
+        <form></form>
+        <ion-fab-button type="submit">Submit</ion-fab-button>
+        <script>
+          const form = document.querySelector('form');
+          const button = document.querySelector('ion-fab-button');
+          button.form = form;
+        </script>
+      `,
+        config
+      );
+
+      const submitEvent = await page.spyOnEvent('submit');
+
+      await page.click('ion-fab-button');
+
+      expect(submitEvent).toHaveReceivedEvent();
+    });
+
+    test('should submit the closest form by pressing the `enter` key on a form input', async ({ page }, testInfo) => {
+      testInfo.annotations.push({
+        type: 'issue',
+        description: 'https://github.com/ionic-team/ionic-framework/issues/18550',
+      });
+
+      await page.setContent(
+        `
+        <form>
+          <input type="text" />
+          <ion-fab-button type="submit">Submit</ion-fab-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 }) => {
+      await page.setContent(
+        `
+        <form>
+          <input type="text" />
+          <ion-fab-button type="submit" disabled>Submit</ion-fab-button>
+        </form>
+      `,
+        config
+      );
+
+      const submitEvent = await page.spyOnEvent('submit');
+
+      await page.press('input', 'Enter');
+
+      expect(submitEvent).not.toHaveReceivedEvent();
+    });
+
+    test('should reset the form', async ({ page }) => {
+      await page.setContent(
+        `
+        <form>
+          <input type="text" value="initial" />
+          <ion-fab-button type="reset">Reset</ion-fab-button>
+        </form>
+      `,
+        config
+      );
+
+      const input = page.locator('input');
+      await input.fill('changed');
+      expect(await input.inputValue()).toBe('changed');
+
+      await page.click('ion-fab-button');
+
+      expect(await input.inputValue()).toBe('initial');
+    });
+  });
+
+  test.describe(title('should throw a warning if the form cannot be found'), () => {
+    test('form is a string selector', async ({ page }) => {
+      const logs: string[] = [];
+
+      page.on('console', (msg) => {
+        if (msg.type() === 'warning') {
+          logs.push(msg.text());
+        }
+      });
+
+      await page.setContent(`<ion-fab-button type="submit" form="missingForm">Submit</ion-fab-button>`, config);
+
+      expect(logs.length).toBe(1);
+      expect(logs[0]).toContain(
+        '[Ionic Warning]: [ion-fab-button] - Form with selector: "#missingForm" could not be found. Verify that the id is correct and the form is rendered in the DOM.'
+      );
+    });
+  });
+});
diff --git a/core/src/components/fab-button/test/form/fab-button.spec.ts b/core/src/components/fab-button/test/form/fab-button.spec.ts
new file mode 100644
index 00000000000..48c0c527a82
--- /dev/null
+++ b/core/src/components/fab-button/test/form/fab-button.spec.ts
@@ -0,0 +1,31 @@
+import { newSpecPage } from '@stencil/core/testing';
+
+import { FabButton } from '../../fab-button';
+
+describe('FabButton: Hidden Form Button', () => {
+  it('should not add multiple buttons to the form on re-render', async () => {
+    const page = await newSpecPage({
+      components: [FabButton],
+      html: `
+        <form id="my-form"></form>
+        <ion-fab-button form="my-form" type="submit">Submit</ion-fab-button>
+      `,
+    });
+
+    const getButtons = () => {
+      return page.body.querySelectorAll('form button');
+    };
+
+    const fabButton = page.body.querySelector('ion-fab-button')!;
+
+    await page.waitForChanges();
+
+    expect(getButtons().length).toEqual(1);
+
+    // Re-render the component by changing a prop
+    fabButton.color = 'danger';
+    await page.waitForChanges();
+
+    expect(getButtons().length).toEqual(1);
+  });
+});
diff --git a/core/src/components/fab-button/test/form/index.html b/core/src/components/fab-button/test/form/index.html
new file mode 100644
index 00000000000..d64c19bc41a
--- /dev/null
+++ b/core/src/components/fab-button/test/form/index.html
@@ -0,0 +1,66 @@
+<!DOCTYPE html>
+<html lang="en" dir="ltr">
+  <head>
+    <meta charset="UTF-8" />
+    <title>FAB Button - Form Submit</title>
+    <meta
+      name="viewport"
+      content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"
+    />
+    <link href="../../../../../css/ionic.bundle.css" rel="stylesheet" />
+    <link href="../../../../../scripts/testing/styles.css" rel="stylesheet" />
+    <script src="../../../../../scripts/testing/scripts.js"></script>
+    <script nomodule src="../../../../../dist/ionic/ionic.js"></script>
+    <script type="module" src="../../../../../dist/ionic/ionic.esm.js"></script>
+  </head>
+
+  <body>
+    <ion-app>
+      <ion-header>
+        <ion-toolbar>
+          <ion-title>FAB Button - Form Submit</ion-title>
+        </ion-toolbar>
+      </ion-header>
+
+      <ion-content class="ion-padding" id="content">
+        <p>The FAB button below is inside the form. Clicking it should submit the form.</p>
+        <form onsubmit="handleSubmit(event)" action="http://httpbin.org/get" method="GET">
+          <ion-list>
+            <ion-item>
+              <ion-input label="Name" name="name" required placeholder="Enter name"></ion-input>
+            </ion-item>
+          </ion-list>
+
+          <ion-fab vertical="bottom" horizontal="end" slot="fixed">
+            <ion-fab-button type="submit">
+              <ion-icon name="cloud-upload-outline"></ion-icon>
+            </ion-fab-button>
+          </ion-fab>
+        </form>
+
+        <br /><br />
+
+        <p>The FAB button below is outside the form but linked by id. Clicking it should also submit the form.</p>
+        <form id="outside-form" onsubmit="handleSubmit(event)" action="http://httpbin.org/get" method="GET">
+          <ion-list>
+            <ion-item>
+              <ion-input label="Email" name="email" type="email" required placeholder="Enter email"></ion-input>
+            </ion-item>
+          </ion-list>
+        </form>
+
+        <ion-fab-button form="outside-form" type="submit">
+          <ion-icon name="checkmark-outline"></ion-icon>
+        </ion-fab-button>
+      </ion-content>
+    </ion-app>
+
+    <script>
+      function handleSubmit(event) {
+        event.preventDefault();
+        console.log('Form submitted!', event.target);
+        alert('Form submitted! Check console for details.');
+      }
+    </script>
+  </body>
+</html>