Update dom.js

dom.js.md

@@ -2,12 +2,29 @@
 import { el, dom }  from './dom.js
 ```
 
-## el(attr, children)
+## el.TAG(attr, children) → Element
+
+This is a proxy for `DomHelper.create`, saving you a few characters. TAG can be any valid HTML tag, attr is an object of attributes to assign using `apply()`, and children is an array of children to append using `append()`.
 
 ## class dom (DomHelper)
 
-### create(element, attr, children)
+### create(element, attr, children) → Element
 
 ### apply(element, attributes)
 
-### append(element, children)
+Apply will apply all values in the **attributes** object as attributes to the element, with a few exceptions:
+
+- If the value of the attribute is null, the attribute will be removed rather than set.
+- If the value of the attribute is true, the attribute value will be the same as the attribute name.
+- If the attribute name starts with `on:`, for example `on:click`, the value must be a callable which will be set as a listener for the specified event. No attribute will be added in this case.
+
+Note: Since this method is called from `el()` and `create()`, the above rules are valid with those methods as well.
+
+### append(element, children)
+
+Append will add all values and elements in the **children** array as children to the element, with a few exceptions:
+
+- If the child is `null`, it will be skipped. This lets you add children conditionally by nulling them if undesired.
+- If the child is a string, it will be added as a text node.
+
+Note: Since this method is called from `el()` and `create()`, the above rules are valid with those methods as well.