git ssb

1
const nest = require('depnest')
2
const { h } = require('mutant')
3
4
exports.gives = nest('app.html.scroller')
5
6
exports.create = function (api) {
7
  return nest('app.html.scroller', Scroller)
8
9
  function Scroller ({ prepend = [], content = null, append = [] } = {}) {
10
    content = content || h('section.content')
11
12
    const container = h('Scroller', { style: { overflow: 'auto' } }, [
13
      h('div.wrapper', [
14
        h('header', prepend),
15
        content,
16
        h('footer', append)
17
      ])
18
    ])
19
20
    container.scroll = keyscroll(content)
21
22
    return {
23
      content,
24
      container
25
    }
26
  }
27
}
28
29
function keyscroll (container) {
30
  var curMsgEl
31
32
  if (!container) return () => {}
33
34
  container.addEventListener('click', onActivateChild, false)
35
  container.addEventListener('focus', onActivateChild, true)
36
37
  function onActivateChild (ev) {
38
    for (var el = ev.target; el; el = el.parentNode) {
39
      if (el.parentNode === container) {
40
        curMsgEl = el
41
        return
42
      }
43
    }
44
  }
45
46
  function selectChild (el) {
47
    if (!el) { return }
48
49
    ;(el.scrollIntoViewIfNeeded || el.scrollIntoView).call(el)
50
    el.focus()
51
    curMsgEl = el
52
  }
53
54
  return function scroll (d) {
55
    selectChild((!curMsgEl || d === 'first') ? container.firstChild
56
      : d < 0 ? curMsgEl.previousElementSibling || container.firstChild
57
      : d > 0 ? curMsgEl.nextElementSibling || container.lastChild
58
      : curMsgEl)
59
60
    return curMsgEl
61
  }
62
}
63