Use `LinkButton` in Excerpt

src/sidebar/components/Excerpt.js

@@ -5,6 +5,8 @@ import observeElementSize from '../util/observe-element-size';
 import { withServices } from '../service-context';
 import { applyTheme } from '../helpers/theme';
 
+import { LinkButton } from '../../shared/components/buttons';
+
 /**
  * @typedef InlineControlsProps
  * @prop {boolean} isCollapsed
@@ -23,17 +25,18 @@ function InlineControls({ isCollapsed, setCollapsed, linkStyle = {} }) {
 
   return (
     <div className="Excerpt__inline-controls">
-      <span className="Excerpt__toggle-link">
-        <button
-          className="Excerpt__toggle-button"
+      <div className="Excerpt__toggle-container">
+        <LinkButton
+          className="InlineLinkButton"
           onClick={() => setCollapsed(!isCollapsed)}
-          aria-expanded={!isCollapsed}
-          aria-label="Toggle visibility of full excerpt text"
+          expanded={!isCollapsed}
+          title="Toggle visibility of full excerpt text"
           style={linkStyle}
+          variant="dark"
         >
           {toggleLabel}
-        </button>
-      </span>
+        </LinkButton>
+      </div>
     </div>
   );
 }

src/sidebar/components/test/Excerpt-test.js

@@ -115,36 +115,48 @@ describe('Excerpt', () => {
   });
 
   context('when inline controls are enabled', () => {
+    const getToggleButton = wrapper =>
+      wrapper.find(
+        'LinkButton[title="Toggle visibility of full excerpt text"]'
+      );
+
     it('displays inline controls if collapsed', () => {
       const wrapper = createExcerpt({ inlineControls: true }, TALL_DIV);
-      assert.isTrue(wrapper.exists('.Excerpt__inline-controls'));
+      assert.isTrue(wrapper.exists('InlineControls'));
     });
 
     it('does not display inline controls if not collapsed', () => {
       const wrapper = createExcerpt({ inlineControls: true }, SHORT_DIV);
-      assert.isFalse(wrapper.exists('.Excerpt__inline-controls'));
+      assert.isFalse(wrapper.exists('InlineControls'));
     });
 
     it('toggles the expanded state when clicked', () => {
       const wrapper = createExcerpt({ inlineControls: true }, TALL_DIV);
-      const button = wrapper.find('.Excerpt__toggle-button');
+      const button = getToggleButton(wrapper);
       assert.equal(getExcerptHeight(wrapper), 40);
-      button.simulate('click');
+      act(() => {
+        button.props().onClick();
+      });
+      wrapper.update();
       assert.equal(getExcerptHeight(wrapper), 200);
     });
 
     it("sets button's default state to un-expanded", () => {
       const wrapper = createExcerpt({ inlineControls: true }, TALL_DIV);
-      const button = wrapper.find('.Excerpt__toggle-button');
-      assert.equal(button.prop('aria-expanded'), false);
+      const button = getToggleButton(wrapper);
+      assert.equal(button.prop('expanded'), false);
       assert.equal(button.text(), 'More');
     });
 
     it("changes button's state to expanded when clicked", () => {
       const wrapper = createExcerpt({ inlineControls: true }, TALL_DIV);
-      wrapper.find('.Excerpt__toggle-button').simulate('click');
-      const button = wrapper.find('.Excerpt__toggle-button');
-      assert.equal(button.prop('aria-expanded'), true);
+      let button = getToggleButton(wrapper);
+      act(() => {
+        button.props().onClick();
+      });
+      wrapper.update();
+      button = getToggleButton(wrapper);
+      assert.equal(button.prop('expanded'), true);
       assert.equal(button.text(), 'Less');
     });
   });

src/styles/sidebar/components/Excerpt.scss

-@use "../../mixins/buttons";
 @use "../../variables" as var;
 
 // the distance by which the shadow indicating a collapsed
@@ -34,7 +33,9 @@ $expand-duration: 0.15s;
   bottom: 0;
 }
 
-.Excerpt__toggle-link {
+// A container for a button with a gradient background; this gives partial
+// opacity behind the More/Less button so that it is easier to read
+.Excerpt__toggle-container {
   padding-left: var.$layout-space;
   // See https://stackoverflow.com/a/56548711/9788954 regarding
   // rgba(255, 255, 255, 0) used here instead of `transparent` (for Safari)
@@ -45,13 +46,6 @@ $expand-duration: 0.15s;
   );
 }
 
-// TODO the tap target here is quite small
-.Excerpt__toggle-button {
-  @include buttons.reset-native-btn-styles;
-  background: transparent;
-  font-style: italic;
-}
-
 // a shadow displayed at the bottom of an <excerpt>s with inline controls
 // disabled, which provides a hint that the excerpt is collapsed
 .Excerpt__shadow {