Event for when element is inserted into the DOM about nanohtml

[shama]

This is a better pattern:

var div = bel`<div onload=${function () {
  document.addEventListener('mousedown', function () {
    if (notTheMenu) hideMenu()
  })
}}>menu</div>`

and use the onBeforeMorphEl hook in morphdom.

Probably should add onunload as well for removing event listeners.

[shama]

The morphdom hooks work when .update() is called but we don't have a solution for when document.body.appendChild(element) is called on an element.

There are some CSS animation hacks for onload but that won't work for onunload.

Another option is a MutationObserver but I think that should become it's own library so one could do:

var onload = require('some-lib/onload')
var onunload = require('some-lib/onunload')

var menu = bel`<div>testing</div>`

onload(menu, function () {
  document.addEventListener('mousedown', hideMenu)
})
onunload(menu, function () {
  document.removeEventListener('mousedown', hideMenu)
})

[shama]

Created a library for it here: https://github.com/shama/on-load