Add `href` etc to sl-icon-button (#496)

* perf: only calculate the used button template

* feat: add href and friends to icon-button

closes #495

docs/components/icon-button.md

@@ -49,6 +49,14 @@ Icon buttons are designed to have a uniform appearance, so their color is not in
 </style>
 ```
 
+### Link Buttons
+
+Use the `href` attribute to convert the button to a link.
+
+```html preview
+<sl-icon-button name="gear" label="Settings" href="https://example.com" target="_blank"></sl-icon-button>
+```
+
 ### Icon Button with Tooltip
 
 Wrap a tooltip around an icon button to provide contextual information to the user.

src/components/button/button.ts

@@ -153,44 +153,7 @@ export default class SlButton extends LitElement {
       ${this.loading ? html`<sl-spinner></sl-spinner>` : ''}
     `;
 
-    const button = html`
-      <button
-        part="base"
-        class=${classMap({
-          button: true,
-          'button--default': this.type === 'default',
-          'button--primary': this.type === 'primary',
-          'button--success': this.type === 'success',
-          'button--info': this.type === 'info',
-          'button--warning': this.type === 'warning',
-          'button--danger': this.type === 'danger',
-          'button--text': this.type === 'text',
-          'button--small': this.size === 'small',
-          'button--medium': this.size === 'medium',
-          'button--large': this.size === 'large',
-          'button--caret': this.caret,
-          'button--circle': this.circle,
-          'button--disabled': this.disabled,
-          'button--focused': this.hasFocus,
-          'button--loading': this.loading,
-          'button--pill': this.pill,
-          'button--has-label': this.hasLabel,
-          'button--has-prefix': this.hasPrefix,
-          'button--has-suffix': this.hasSuffix
-        })}
-        ?disabled=${this.disabled}
-        type=${this.submit ? 'submit' : 'button'}
-        name=${ifDefined(this.name)}
-        value=${ifDefined(this.value)}
-        @blur=${this.handleBlur}
-        @focus=${this.handleFocus}
-        @click=${this.handleClick}
-      >
-        ${interior}
-      </button>
-    `;
-
-    const link = html`
+    return isLink ? html`
       <a
         ref=${(el: HTMLLinkElement) => (this.button = el)}
         part="base"
@@ -229,9 +192,42 @@ export default class SlButton extends LitElement {
       >
         ${interior}
       </a>
+    ` : html`
+      <button
+        part="base"
+        class=${classMap({
+          button: true,
+          'button--default': this.type === 'default',
+          'button--primary': this.type === 'primary',
+          'button--success': this.type === 'success',
+          'button--info': this.type === 'info',
+          'button--warning': this.type === 'warning',
+          'button--danger': this.type === 'danger',
+          'button--text': this.type === 'text',
+          'button--small': this.size === 'small',
+          'button--medium': this.size === 'medium',
+          'button--large': this.size === 'large',
+          'button--caret': this.caret,
+          'button--circle': this.circle,
+          'button--disabled': this.disabled,
+          'button--focused': this.hasFocus,
+          'button--loading': this.loading,
+          'button--pill': this.pill,
+          'button--has-label': this.hasLabel,
+          'button--has-prefix': this.hasPrefix,
+          'button--has-suffix': this.hasSuffix
+        })}
+        ?disabled=${this.disabled}
+        type=${this.submit ? 'submit' : 'button'}
+        name=${ifDefined(this.name)}
+        value=${ifDefined(this.value)}
+        @blur=${this.handleBlur}
+        @focus=${this.handleFocus}
+        @click=${this.handleClick}
+      >
+        ${interior}
+      </button>
     `;
-
-    return isLink ? link : button;
   }
 }
 

src/components/icon-button/icon-button.ts

@@ -19,7 +19,7 @@ import '../icon/icon';
 export default class SlIconButton extends LitElement {
   static styles = styles;
 
-  @query('button') button: HTMLButtonElement;
+  @query('button') button: HTMLButtonElement|HTMLLinkElement;
 
   /** The name of the icon to draw. */
   @property() name: string;
@@ -30,6 +30,15 @@ export default class SlIconButton extends LitElement {
   /** An external URL of an SVG file. */
   @property() src: string;
 
+  /** When set, the underlying button will be rendered as an `<a>` with this `href` instead of a `<button>`. */
+  @property() href: string;
+
+  /** Tells the browser where to open the link. Only used when `href` is set. */
+  @property() target: '_blank' | '_parent' | '_self' | '_top';
+
+  /** Tells the browser to download the linked file as this filename. Only used when `href` is set. */
+  @property() download: string;
+
   /**
    * A description that gets read by screen readers and other assistive devices. For optimal accessibility, you should
    * always include a label that describes what the icon button does.
@@ -50,7 +59,34 @@ export default class SlIconButton extends LitElement {
   }
 
   render() {
-    return html`
+    const isLink = this.href ? true : false;
+
+    const interior = html`
+      <sl-icon
+        name=${ifDefined(this.name)}
+        library=${ifDefined(this.library)}
+        src=${ifDefined(this.src)}
+        aria-hidden="true"
+      ></sl-icon>
+    `;
+
+    return isLink ? html`
+    <a
+      ref=${(el: HTMLLinkElement) => (this.button = el)}
+      part="base"
+      class="icon-button"
+      href=${ifDefined(this.href)}
+      target=${ifDefined(this.target)}
+      download=${ifDefined(this.download)}
+      rel=${ifDefined(this.target ? 'noreferrer noopener' : undefined)}
+      role="button"
+      aria-disabled=${this.disabled ? 'true' : 'false'}
+      aria-label="${this.label}"
+      tabindex=${this.disabled ? '-1' : '0'}
+    >
+      ${interior}
+    </a>
+    ` : html`
       <button
         part="base"
         class=${classMap({
@@ -61,12 +97,7 @@ export default class SlIconButton extends LitElement {
         type="button"
         aria-label=${this.label}
       >
-        <sl-icon
-          name=${ifDefined(this.name)}
-          library=${ifDefined(this.library)}
-          src=${ifDefined(this.src)}
-          aria-hidden="true"
-        ></sl-icon>
+        ${interior}
       </button>
     `;
   }