docs(helpers): add 'Helpers > Stretched link' page (#2719)

Co-authored-by: Julien Déramond <[email protected]>

site/content/docs/0.0/helpers/stretched-link.md

@@ -7,4 +7,70 @@ aliases:
   - "/docs/helpers/stretched-link/"
 ---
 
-{{< callout-soon "helper" >}}
+Add `.stretched-link` to a link to make its [containing block](https://developer.mozilla.org/en-US/docs/Web/CSS/Containing_block) clickable via a `::after` pseudo element. In most cases, this means that an element with `position: relative;` that contains a link with the `.stretched-link` class is clickable. Please note given [how CSS `position` works](https://www.w3.org/TR/CSS21/visuren.html#propdef-position), `.stretched-link` cannot be mixed with most table elements.
+
+<!--Cards have `position: relative` by default in OUDS Web, so in this case you can safely add the `.stretched-link` class to a link in the card without any other HTML changes.-->
+
+Multiple links and tap targets are not recommended with stretched links. However, some `position` and `z-index` styles can help should this be required.
+
+<!--{{< example >}}
+<div class="card" style="width: 18rem;">
+  { {< placeholder width="100%" height="180" class="card-img-top" text="false" title="Card image cap" >}}
+  <div class="card-body">
+    <h5 class="card-title">Card with stretched link</h5>
+    <p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
+    <a href="#" class="btn btn-primary stretched-link">Go somewhere</a>
+  </div>
+</div>
+{{< /example >}}-->
+
+Most custom components do not have `position: relative` by default, so we need to add the `.position-relative` here to prevent the link from stretching outside the parent element.
+
+{{< example >}}
+<div class="d-flex position-relative">
+  {{< placeholder width="144" height="144" class="flex-shrink-0 me-3" text="false" title="Generic placeholder image" >}}
+  <div>
+    <h5 class="mt-0">Custom component with stretched link</h5>
+    <p>This is some placeholder content for the custom component. It is intended to mimic what some real-world content would look like, and we're using it here to give the component a bit of body and size.</p>
+    <a href="#" class="stretched-link">Go somewhere</a>
+  </div>
+</div>
+{{< /example >}}
+
+<!--{{< example >}}
+<div class="row g-0 bg-body-secondary position-relative">
+  <div class="col-md-6 mb-md-0 p-md-4">
+    { {< placeholder width="100%" height="200" class="w-100" text="false" title="Generic placeholder image" >}}
+  </div>
+  <div class="col-md-6 p-4 ps-md-0">
+    <h5 class="mt-0">Columns with stretched link</h5>
+    <p>Another instance of placeholder content for this other custom component. It is intended to mimic what some real-world content would look like, and we're using it here to give the component a bit of body and size.</p>
+    <a href="#" class="stretched-link">Go somewhere</a>
+  </div>
+</div>
+{{< /example >}}-->
+
+## Identifying the containing block
+
+If the stretched link doesn't seem to work, the [containing block](https://developer.mozilla.org/en-US/docs/Web/CSS/Containing_block#Identifying_the_containing_block) will probably be the cause. The following CSS properties will make an element the containing block:
+
+- A `position` value other than `static`
+- A `transform` or `perspective` value other than `none`
+- A `will-change` value of `transform` or `perspective`
+- A `filter` value other than `none` or a `will-change` value of `filter` (only works on Firefox)
+
+<!--{{< example >}}
+<div class="card" style="width: 18rem;">
+  { {< placeholder width="100%" height="180" class="card-img-top" text="false" title="Card image cap" >}}
+  <div class="card-body">
+    <h5 class="card-title">Card with stretched links</h5>
+    <p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
+    <p class="card-text">
+      <a href="#" class="stretched-link text-danger" style="position: relative;">Stretched link will not work here, because <code>position: relative</code> is added to the link</a>
+    </p>
+    <p class="card-text bg-body-tertiary" style="transform: rotate(0);">
+      This <a href="#" class="text-warning stretched-link">stretched link</a> will only be spread over the <code>p</code>-tag, because a transform is applied to it.
+    </p>
+  </div>
+</div>
+{{< /example >}}-->

site/data/sidebar.yml

@@ -193,7 +193,6 @@
       draft: true
     - title: Stacks
     - title: Stretched link
-      draft: true
     - title: Text truncation
     - title: Vertical rule
       draft: true