Add DOM find snippets

snippets/findClosestAnchor.md

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+---
+title: findClosestAnchor
+tags: browser,intermediate
+---
+
+Finds the anchor node closest to the given `node`, if any.
+
+- Use a `for` loop and `Node.parentNode` to traverse the node tree upwards from the given `node`.
+- Use `Node.nodeName` and `String.prototype.toLowerCase()` to check if any given node is an anchor (`'a'`).
+- If no matching node is found, return `null`.
+
+```js
+const findClosestAnchor = node => {
+  for (let n = node; n.parentNode; n = n.parentNode)
+    if (n.nodeName.toLowerCase() === 'a') return n;
+  return null;
+};
+```
+
+```js
+findClosestAnchor(document.querySelector('a > span')); // a
+```

snippets/findClosestMatchingNode.md

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+---
+title: findClosestMatchingNode
+tags: browser,intermediate
+---
+
+Finds the closest matching node starting at the given `node`.
+
+- Use a `for` loop and `Node.parentNode` to traverse the node tree upwards from the given `node`.
+- Use `Element.matches()` to check if any given element node matches the provided `selector`.
+- If no matching node is found, return `null`.
+
+```js
+const findClosestMatchingNode = (node, selector) => {
+  for (let n = node; n.parentNode; n = n.parentNode)
+    if (n.matches && n.matches(selector)) return n;
+  return null;
+};
+```
+
+```js
+findClosestMatchingNode(document.querySelector('span'), 'body'); // body
+```