Add renderElement snippet

snippets/renderElement.md

@@ -0,0 +1,54 @@
+---
+title: renderElement
+tags: browser,recursion,advanced
+---
+
+Renders the given DOM tree in the specified DOM element.
+
+Destructure the first argument into `type` and `props`, use `type` to determine if the given element is a text element.
+Based on the element's `type`, use either `Document.createTextNode()` or `Document.createElement()` to create the DOM element.
+Use `Object.keys(props`, adding attributes to the DOM element and setting event listeners, as necessary.
+Use recursion to render `props.children`, if any.
+Finally, use `Node.appendChild()` to append the DOM element to the specified `container`.
+
+```js
+const renderElement = ({ type, props = {} }, container) => {
+  const isTextElement = !type;
+  const element = isTextElement
+    ? document.createTextNode('')
+    : document.createElement(type);
+
+  const isListener = p => p.startsWith('on');
+  const isAttribute = p => !isListener(p) && p !== 'children';
+
+  Object.keys(props).forEach(p => {
+    if(isAttribute(p)) element[p] = props[p];
+    if(!isTextElement && isListener(p))
+      element.addEventListener(p.toLowerCase().slice(2), props[p]);
+  });
+
+  if(!isTextElement && props.children && props.children.length)
+    props.children.forEach(childElement => renderElement(childElement, element));
+
+  container.appendChild(element);
+}
+```
+
+```js
+const myElement = {
+  type: 'button',
+  props: {
+    type: 'button',
+    className: 'btn',
+    onClick: () => alert('Clicked'),
+    children: [
+      { props: { nodeValue: 'Click me' } }
+    ]
+  }
+};
+
+renderElement(
+  myElement,
+  document.body
+);
+```