feat(material-experimental/mdc-slide-toggle): switch to non-deprecated styles

Switches the MDC-based slide toggle to the non-deprecated MDC styles.

Notable changes:
* New markup which uses a `button` instead of an `input` for the button.
* New icons inside the slide toggle's thumb. Technically we could opt out of them, but I think that they look better and they help with accessibility for color-blind users.
* New theming system that uses a flat list of variables. There is a fallback for IE11, but I opted not to include it for now, because of the upcoming deprecation and the fact that the component is in experimental.
* The component has some slightly different colors and it supports more states (e.g. hover).
* Due to the switch from `input` to `button`, the `required` input is basically a noop now.

Author: crisbeto

scripts/check-mdc-tests-config.ts

@@ -175,6 +175,10 @@ export const config = {
       'should re-add margin if label is added asynchronously',
       'should properly update margin if label content is projected',
 
+      // The MDC implementation uses a `button` instead of an `input` which can't be required.
+      'should forward the required attribute',
+      'should prevent the form from submit when being required',
+
       // TODO: the focus origin functionality has to be implemeted for the MDC slide toggle.
       'should not change focus origin if origin not specified'
     ],

src/material-experimental/mdc-helpers/_focus-indicators.scss

@@ -60,7 +60,8 @@
   // which will clip a square focus indicator so we have to turn it into a circle.
   .mat-mdc-checkbox-ripple.mat-mdc-focus-indicator::before,
   .mat-radio-ripple.mat-mdc-focus-indicator::before,
-  .mat-mdc-slider .mat-mdc-focus-indicator::before {
+  .mat-mdc-slider .mat-mdc-focus-indicator::before,
+  .mat-mdc-slide-toggle .mat-mdc-focus-indicator::before {
     border-radius: 50%;
   }
 

src/material-experimental/mdc-slide-toggle/_slide-toggle-theme.scss

@@ -1,103 +1,140 @@
-@use '@material/theme/theme-color' as mdc-theme-color;
-@use '@material/switch/deprecated' as mdc-switch with ($deprecated-suffix: '');
-@use '@material/form-field' as mdc-form-field;
 @use 'sass:map';
+@use 'sass:color';
+@use '@material/switch/switch-theme' as mdc-switch-theme;
+@use '@material/theme/color-palette' as mdc-color-palette;
+@use '@material/form-field' as mdc-form-field;
 @use '../mdc-helpers/mdc-helpers';
 @use '../../material/core/typography/typography';
 @use '../../material/core/theming/theming';
+@use '../../material/core/theming/palette';
+
+// Generates all color mapping for the properties that only change based on the theme.
+@function _get-theme-base-map($is-dark) {
+  $on-surface: if($is-dark, mdc-color-palette.$grey-100, mdc-color-palette.$grey-800);
+  $hairline: if($is-dark, mdc-color-palette.$grey-500, mdc-color-palette.$grey-300);
+  $on-surface-variant: if($is-dark, mdc-color-palette.$grey-200, mdc-color-palette.$grey-700);
+  $on-surface-state-content: if($is-dark, mdc-color-palette.$grey-50, mdc-color-palette.$grey-900);
+  $disabled-handle-color: mdc-color-palette.$grey-800;
+  $selected-icon-color: mdc-color-palette.$grey-100;
+  $icon-color: if($is-dark, mdc-color-palette.$grey-800, mdc-color-palette.$grey-100);
+
+  @return (
+    disabled-selected-handle-color: $disabled-handle-color,
+    disabled-unselected-handle-color: $disabled-handle-color,
+
+    disabled-selected-track-color: $on-surface,
+    disabled-unselected-track-color: $on-surface,
+    unselected-focus-state-layer-color: $on-surface,
+    unselected-pressed-state-layer-color: $on-surface,
+    unselected-hover-state-layer-color: $on-surface,
+
+    unselected-focus-track-color: $hairline,
+    unselected-hover-track-color: $hairline,
+    unselected-pressed-track-color: $hairline,
+    unselected-track-color: $hairline,
+
+    unselected-focus-handle-color: $on-surface-state-content,
+    unselected-hover-handle-color: $on-surface-state-content,
+    unselected-pressed-handle-color: $on-surface-state-content,
+
+    handle-surface-color: surface,
+    unselected-handle-color: $on-surface-variant,
+
+    selected-icon-color: $selected-icon-color,
+    disabled-selected-icon-color: $icon-color,
+    disabled-unselected-icon-color: $icon-color,
+    unselected-icon-color: $icon-color,
+  );
+}
 
+// Generates the mapping for the properties that change based on the slide toggle color.
+@function _get-theme-color-map($color-palette) {
+  $state-content: color.scale($color-palette, $blackness: 50%);
+  $inverse: color.scale($color-palette, $lightness: 75%);
+
+  @return (
+    selected-focus-state-layer-color: $color-palette,
+    selected-handle-color: $color-palette,
+    selected-hover-state-layer-color: $color-palette,
+    selected-pressed-state-layer-color: $color-palette,
+
+    selected-focus-handle-color: $state-content,
+    selected-hover-handle-color: $state-content,
+    selected-pressed-handle-color: $state-content,
+
+    selected-focus-track-color: $inverse,
+    selected-hover-track-color: $inverse,
+    selected-pressed-track-color: $inverse,
+    selected-track-color: $inverse,
+  );
+}
 
 @mixin color($config-or-theme) {
   $config: theming.get-color-config($config-or-theme);
   $primary: theming.get-color-from-palette(map.get($config, primary));
   $accent: theming.get-color-from-palette(map.get($config, accent));
   $warn: theming.get-color-from-palette(map.get($config, warn));
-
-  // Save original values of MDC global variables. We need to save these so we can restore the
-  // variables to their original values and prevent unintended side effects from using this mixin.
-  $orig-baseline-theme-color: mdc-switch.$baseline-theme-color;
-  $orig-toggled-off-thumb-color: mdc-switch.$toggled-off-thumb-color;
-  $orig-toggled-off-track-color: mdc-switch.$toggled-off-track-color;
-  $orig-disabled-thumb-color: mdc-switch.$disabled-thumb-color;
-  $orig-disabled-track-color: mdc-switch.$disabled-track-color;
+  $is-dark: map.get($config, is-dark);
 
   @include mdc-helpers.mat-using-mdc-theme($config) {
-    mdc-switch.$baseline-theme-color: primary;
-    mdc-switch.$toggled-off-thumb-color: mdc-theme-color.prop-value(surface);
-    mdc-switch.$toggled-off-track-color: mdc-theme-color.prop-value(on-surface);
-    mdc-switch.$disabled-thumb-color: mdc-theme-color.prop-value(surface);
-    mdc-switch.$disabled-track-color: mdc-theme-color.prop-value(on-surface);
-
     // MDC's switch doesn't support a `color` property. We add support
     // for it by adding a CSS class for accent and warn style.
     .mat-mdc-slide-toggle {
       @include mdc-form-field.core-styles($query: mdc-helpers.$mat-theme-styles-query);
-
-      .mdc-switch__thumb-underlay::after, .mat-ripple-element {
-        background: mdc-switch.$toggled-off-ripple-color;
-      }
+      @include mdc-switch-theme.theme(_get-theme-base-map($is-dark));
 
       &.mat-primary {
-        @include mdc-switch.without-ripple($query: mdc-helpers.$mat-theme-styles-query);
+        @include mdc-switch-theme.theme(_get-theme-color-map($primary));
       }
 
       &.mat-accent {
-        mdc-switch.$baseline-theme-color: secondary;
-        @include mdc-switch.without-ripple($query: mdc-helpers.$mat-theme-styles-query);
+        @include mdc-switch-theme.theme(_get-theme-color-map($accent));
       }
 
       &.mat-warn {
-        mdc-switch.$baseline-theme-color: error;
-        @include mdc-switch.without-ripple($query: mdc-helpers.$mat-theme-styles-query);
+        @include mdc-switch-theme.theme(_get-theme-color-map($warn));
       }
     }
 
     // The ripple color matches the palette only when it's checked.
     .mat-mdc-slide-toggle-checked {
-      .mdc-switch__thumb-underlay::after, .mat-ripple-element {
+      .mdc-switch__ripple::after, .mat-ripple-element {
         background: $primary;
       }
 
       &.mat-accent {
-        .mdc-switch__thumb-underlay::after, .mat-ripple-element {
+        .mdc-switch__ripple::after, .mat-ripple-element {
           background: $accent;
         }
       }
 
       &.mat-warn {
-        .mdc-switch__thumb-underlay::after, .mat-ripple-element {
+        .mdc-switch__ripple::after, .mat-ripple-element {
           background: $warn;
         }
       }
     }
   }
-
-  // Restore original values of MDC global variables.
-  mdc-switch.$baseline-theme-color: $orig-baseline-theme-color;
-  mdc-switch.$toggled-off-thumb-color: $orig-toggled-off-thumb-color;
-  mdc-switch.$toggled-off-track-color: $orig-toggled-off-track-color;
-  mdc-switch.$disabled-thumb-color: $orig-disabled-thumb-color;
-  mdc-switch.$disabled-track-color: $orig-disabled-track-color;
 }
 
 @mixin typography($config-or-theme) {
   $config: typography.private-typography-to-2018-config(
       theming.get-typography-config($config-or-theme));
   @include mdc-helpers.mat-using-mdc-typography($config) {
-    @include mdc-switch.without-ripple($query: mdc-helpers.$mat-typography-styles-query);
     @include mdc-form-field.core-styles($query: mdc-helpers.$mat-typography-styles-query);
   }
 }
 
 @mixin density($config-or-theme) {
   $density-scale: theming.get-density-config($config-or-theme);
-  .mat-mdc-slide-toggle .mdc-switch {
-    @include mdc-switch.density($density-scale, $query: mdc-helpers.$mat-base-styles-query);
+  .mat-mdc-slide-toggle {
+    @include mdc-switch-theme.theme(mdc-switch-theme.density($density-scale));
   }
 }
 
 @mixin theme($theme-or-color-config) {
   $theme: theming.private-legacy-get-theme($theme-or-color-config);
+
   @include theming.private-check-duplicate-theme-styles($theme, 'mat-mdc-slide-toggle') {
     $color: theming.get-color-config($theme);
     $density: theming.get-density-config($theme);

src/material-experimental/mdc-slide-toggle/slide-toggle.e2e.spec.ts

@@ -3,7 +3,7 @@ import {expectToExist} from '@angular/cdk/testing/private/e2e';
 
 
 describe('MDC-based slide-toggle', () => {
-  const getInput = () => element(by.css('#normal-slide-toggle input'));
+  const getButton = () => element(by.css('#normal-slide-toggle button'));
   const getNormalToggle = () => element(by.css('#normal-slide-toggle'));
 
   beforeEach(async () => await browser.get('mdc-slide-toggle'));
@@ -13,44 +13,44 @@ describe('MDC-based slide-toggle', () => {
   });
 
   it('should change the checked state on click', async () => {
-    const inputEl = getInput();
+    const buttonEl = getButton();
 
-    expect(await inputEl.getAttribute('checked'))
-      .toBeFalsy('Expect slide-toggle to be unchecked');
+    expect(await buttonEl.getAttribute('aria-checked'))
+      .toBe('false', 'Expect slide-toggle to be unchecked');
 
     await getNormalToggle().click();
 
-    expect(await inputEl.getAttribute('checked'))
-      .toBeTruthy('Expect slide-toggle to be checked');
+    expect(await buttonEl.getAttribute('aria-checked'))
+      .toBe('true', 'Expect slide-toggle to be checked');
   });
 
   it('should change the checked state on click', async () => {
-    const inputEl = getInput();
+    const buttonEl = getButton();
 
-    expect(await inputEl.getAttribute('checked'))
-      .toBeFalsy('Expect slide-toggle to be unchecked');
+    expect(await buttonEl.getAttribute('aria-checked'))
+      .toBe('false', 'Expect slide-toggle to be unchecked');
 
     await getNormalToggle().click();
 
-    expect(await inputEl.getAttribute('checked'))
-      .toBeTruthy('Expect slide-toggle to be checked');
+    expect(await buttonEl.getAttribute('aria-checked'))
+      .toBe('true', 'Expect slide-toggle to be checked');
   });
 
   it('should not change the checked state on click when disabled', async () => {
-    const inputEl = getInput();
+    const buttonEl = getButton();
 
-    expect(await inputEl.getAttribute('checked'))
-      .toBeFalsy('Expect slide-toggle to be unchecked');
+    expect(await buttonEl.getAttribute('aria-checked'))
+      .toBe('false', 'Expect slide-toggle to be unchecked');
 
     await element(by.css('#disabled-slide-toggle')).click();
 
-    expect(await inputEl.getAttribute('checked'))
-      .toBeFalsy('Expect slide-toggle to be unchecked');
+    expect(await buttonEl.getAttribute('aria-checked'))
+      .toBe('false', 'Expect slide-toggle to be unchecked');
   });
 
   it('should move the thumb on state change', async () => {
     const slideToggleEl = getNormalToggle();
-    const thumbEl = element(by.css('#normal-slide-toggle .mdc-switch__thumb-underlay'));
+    const thumbEl = element(by.css('#normal-slide-toggle .mdc-switch__handle'));
     const previousPosition = await thumbEl.getLocation();
 
     await slideToggleEl.click();
@@ -61,15 +61,15 @@ describe('MDC-based slide-toggle', () => {
   });
 
   it('should toggle the slide-toggle on space key', async () => {
-    const inputEl = getInput();
+    const buttonEl = getButton();
 
-    expect(await inputEl.getAttribute('checked'))
-      .toBeFalsy('Expect slide-toggle to be unchecked');
+    expect(await buttonEl.getAttribute('aria-checked'))
+      .toBe('false', 'Expect slide-toggle to be unchecked');
 
-    await inputEl.sendKeys(Key.SPACE);
+    await buttonEl.sendKeys(Key.SPACE);
 
-    expect(await inputEl.getAttribute('checked'))
-      .toBeTruthy('Expect slide-toggle to be checked');
+    expect(await buttonEl.getAttribute('aria-checked'))
+      .toBe('true', 'Expect slide-toggle to be checked');
   });
 
 });

src/material-experimental/mdc-slide-toggle/slide-toggle.html

@@ -1,33 +1,50 @@
 <div class="mdc-form-field"
      [class.mdc-form-field--align-end]="labelPosition == 'before'">
-  <div class="mdc-switch mat-mdc-switch" #switch>
+  <button
+    class="mdc-switch"
+    role="switch"
+    type="button"
+    [class.mdc-switch--selected]="checked"
+    [class.mdc-switch--unselected]="!checked"
+    [tabIndex]="tabIndex"
+    [disabled]="disabled"
+    [attr.id]="buttonId"
+    [attr.name]="name"
+    [attr.aria-label]="ariaLabel"
+    [attr.aria-labelledby]="_getAriaLabelledBy()"
+    [attr.aria-describedby]="ariaDescribedby"
+    (click)="_handleClick($event)"
+    #switch>
     <div class="mdc-switch__track"></div>
-    <div class="mdc-switch__thumb-underlay mat-mdc-focus-indicator">
-      <div class="mat-mdc-slide-toggle-ripple" mat-ripple
-        [matRippleTrigger]="switch"
-        [matRippleDisabled]="disableRipple || disabled"
-        [matRippleCentered]="true"
-        [matRippleAnimation]="_rippleAnimation"></div>
-      <div class="mdc-switch__thumb">
-          <input #input class="mdc-switch__native-control" type="checkbox"
-            role="switch"
-            [id]="inputId"
-            [required]="required"
-            [tabIndex]="tabIndex"
-            [checked]="checked"
-            [disabled]="disabled"
-            [attr.name]="name"
-            [attr.aria-checked]="checked.toString()"
-            [attr.aria-label]="ariaLabel"
-            [attr.aria-labelledby]="ariaLabelledby"
-            [attr.aria-describedby]="ariaDescribedby"
-            (change)="_onChangeEvent($event)"
-            (click)="_onInputClick($event)">
+    <div class="mdc-switch__handle-track">
+      <div class="mdc-switch__handle">
+        <div class="mdc-switch__shadow">
+          <div class="mdc-elevation-overlay"></div>
+        </div>
+        <div class="mdc-switch__ripple">
+          <div class="mat-mdc-slide-toggle-ripple mat-mdc-focus-indicator" mat-ripple
+            [matRippleTrigger]="switch"
+            [matRippleDisabled]="disableRipple || disabled"
+            [matRippleCentered]="true"
+            [matRippleAnimation]="_rippleAnimation"></div>
+        </div>
+        <div class="mdc-switch__icons">
+          <svg class="mdc-switch__icon mdc-switch__icon--on" viewBox="0 0 24 24">
+            <path d="M19.69,5.23L8.96,15.96l-4.23-4.23L2.96,13.5l6,6L21.46,7L19.69,5.23z" />
+          </svg>
+          <svg class="mdc-switch__icon mdc-switch__icon--off" viewBox="0 0 24 24">
+            <path d="M20 13H4v-2h16v2z" />
+          </svg>
+        </div>
       </div>
     </div>
-  </div>
+  </button>
 
-  <label [for]="inputId">
+  <!--
+    Clicking on the label will trigger another click event from the button.
+    Stop propagation here so other listeners further up in the DOM don't execute twice.
+  -->
+  <label [for]="buttonId" [attr.id]="_labelId" (click)="$event.stopPropagation()">
     <ng-content></ng-content>
   </label>
 </div>