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 (opts = {}) {
10
    const { prepend, content = null, append, classList = [], className = '', title = '' } = opts
11
12
    const contentSection = h('section.content', { title: '' }, content)
13
14
    const container = h('Scroller',
15
      { classList, className, title, style: { 'overflow-y': 'scroll', 'overflow-x': 'auto' } },
16
      [
17
        prepend ? h('section.top', prepend) : null,
18
        contentSection,
19
        append ? h('section.bottom', append) : null
20
      ]
21
    )
22
23
    container.scroll = keyscroll(contentSection)
24
25
    return {
26
      content: contentSection,
27
      container
28
    }
29
  }
30
}
31
32
function keyscroll (content) {
33
  var curMsgEl
34
35
  if (!content) return () => {}
36
37
  content.addEventListener('click', onActivateChild, false)
38
  content.addEventListener('focus', onActivateChild, true)
39
40
  function onActivateChild (ev) {
41
    for (var el = ev.target; el; el = el.parentNode) {
42
      if (el.parentNode === content) {
43
        curMsgEl = el
44
        return
45
      }
46
    }
47
  }
48
49
  return function scroll (d) {
50
    const child = (!curMsgEl || d === 'first') ? content.firstChild
51
      : (!curMsgEl || d === 'last') ? content.lastChild
52
        : d < 0 ? curMsgEl.previousElementSibling || content.firstChild
53
          : d > 0 ? curMsgEl.nextElementSibling || content.lastChild
54
            : curMsgEl
55
    selectChild(child)
56
57
    return curMsgEl
58
  }
59
60
  function selectChild (el) {
61
    if (!el) { return }
62
63
    if (!el.scrollIntoViewIfNeeded && !el.scrollIntoView) return
64
    ;(el.scrollIntoViewIfNeeded || el.scrollIntoView).call(el)
65
    el.focus()
66
    curMsgEl = el
67
  }
68
}
69