signal-desktop/js/views/message_list_view.js
Scott Nonnenberg 3c69886320 Finish new Message component, integrate into application
Also:
- New schema version 8 with video/image thumbnails, screenshots, sizes
- Upgrade messages not at current schema version when loading messages
  to show in conversation
- New MessageDetail react component
- New ConversationHeader react component
2018-07-17 15:58:07 -07:00

113 lines
3.5 KiB
JavaScript

/* global Whisper, _ */
// eslint-disable-next-line func-names
(function() {
'use strict';
window.Whisper = window.Whisper || {};
Whisper.MessageListView = Whisper.ListView.extend({
tagName: 'ul',
className: 'message-list',
itemView: Whisper.MessageView,
events: {
scroll: 'onScroll',
},
initialize() {
Whisper.ListView.prototype.initialize.call(this);
this.triggerLazyScroll = _.debounce(() => {
this.$el.trigger('lazyScroll');
}, 500);
},
onScroll() {
this.measureScrollPosition();
if (this.$el.scrollTop() === 0) {
this.$el.trigger('loadMore');
}
if (this.atBottom()) {
this.$el.trigger('atBottom');
} else if (this.bottomOffset > this.outerHeight) {
this.$el.trigger('farFromBottom');
}
this.triggerLazyScroll();
},
atBottom() {
return this.bottomOffset < 30;
},
measureScrollPosition() {
if (this.el.scrollHeight === 0) {
// hidden
return;
}
this.outerHeight = this.$el.outerHeight();
this.scrollPosition = this.$el.scrollTop() + this.outerHeight;
this.scrollHeight = this.el.scrollHeight;
this.bottomOffset = this.scrollHeight - this.scrollPosition;
},
resetScrollPosition() {
this.$el.scrollTop(this.scrollPosition - this.$el.outerHeight());
},
scrollToBottomIfNeeded() {
// This is counter-intuitive. Our current bottomOffset is reflective of what
// we last measured, not necessarily the current state. And this is called
// after we just made a change to the DOM: inserting a message, or an image
// finished loading. So if we were near the bottom before, we _need_ to be
// at the bottom again. So we scroll to the bottom.
if (this.atBottom()) {
this.scrollToBottom();
}
},
scrollToBottom() {
this.$el.scrollTop(this.el.scrollHeight);
this.measureScrollPosition();
},
addOne(model) {
// eslint-disable-next-line new-cap
const view = new this.itemView({ model }).render();
this.listenTo(view, 'beforeChangeHeight', this.measureScrollPosition);
this.listenTo(view, 'afterChangeHeight', this.scrollToBottomIfNeeded);
const index = this.collection.indexOf(model);
this.measureScrollPosition();
if (model.get('unread') && !this.atBottom()) {
this.$el.trigger('newOffscreenMessage');
}
if (index === this.collection.length - 1) {
// add to the bottom.
this.$el.append(view.el);
} else if (index === 0) {
// add to top
this.$el.prepend(view.el);
} else {
// insert
const next = this.$(`#${this.collection.at(index + 1).id}`);
const prev = this.$(`#${this.collection.at(index - 1).id}`);
if (next.length > 0) {
view.$el.insertBefore(next);
} else if (prev.length > 0) {
view.$el.insertAfter(prev);
} else {
// scan for the right spot
const elements = this.$el.children();
if (elements.length > 0) {
for (let i = 0; i < elements.length; i += 1) {
const m = this.collection.get(elements[i].id);
const mIndex = this.collection.indexOf(m);
if (mIndex > index) {
view.$el.insertBefore(elements[i]);
break;
}
}
} else {
this.$el.append(view.el);
}
}
}
this.scrollToBottomIfNeeded();
},
});
})();