-
Notifications
You must be signed in to change notification settings - Fork 754
/
set-scroll.ts
145 lines (137 loc) · 5.24 KB
/
set-scroll.ts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
import { IncomingPayload } from "../messages/ScrollEvent";
import { Inputs } from "../index";
import { pluck } from "rxjs/operators/pluck";
import { Observable } from "rxjs/Observable";
import { ignoreElements } from "rxjs/operators/ignoreElements";
import { partition } from "rxjs/operators/partition";
import { merge } from "rxjs/observable/merge";
import { getDocumentScrollSpace } from "../browser.utils";
import { tap } from "rxjs/operators/tap";
import { withLatestFrom } from "rxjs/operators/withLatestFrom";
import { map } from "rxjs/operators/map";
type Tuple = [IncomingPayload, Window, Document, boolean];
export function setScrollEffect(
xs: Observable<IncomingPayload>,
inputs: Inputs
) {
{
/**
* Group the incoming event with window, document & scrollProportionally argument
*/
const tupleStream$: Observable<Tuple> = xs.pipe(
withLatestFrom<IncomingPayload, Window, Document, boolean>(
inputs.window$,
inputs.document$,
inputs.option$.pipe(pluck("scrollProportionally"))
)
);
/**
* Split the stream between document scrolls and element scrolls
*/
const [document$, element$] = partition(([event]: Tuple) => {
return event.tagName === "document";
})(tupleStream$);
/**
* Further split the element scroll between those matching in `scrollElementMapping`
* and regular element scrolls
*/
const [mapped$, nonMapped$] = partition(([event]: Tuple) => {
return event.mappingIndex > -1;
})(element$);
return merge(
/**
* Main window scroll
*/
document$.pipe(
tap((incoming: Tuple) => {
const [
event,
window,
document,
scrollProportionally
] = incoming;
const scrollSpace = getDocumentScrollSpace(document);
if (scrollProportionally) {
return window.scrollTo(
0,
scrollSpace.y * event.position.proportional
); // % of y axis of scroll to px
}
return window.scrollTo(0, event.position.raw.y);
})
),
/**
* Regular, non-mapped Element scrolls
*/
nonMapped$.pipe(
tap((incoming: Tuple) => {
const [
event,
window,
document,
scrollProportionally
] = incoming;
const matchingElements = document.getElementsByTagName(
event.tagName
);
if (matchingElements && matchingElements.length) {
const match = matchingElements[event.index];
if (match) {
return scrollElement(
match,
scrollProportionally,
event
);
}
}
})
),
/**
* Element scrolls given in 'scrollElementMapping'
*/
mapped$.pipe(
withLatestFrom(
inputs.option$.pipe(pluck("scrollElementMapping"))
),
/**
* Filter the elements in the option `scrollElementMapping` so
* that it does not contain the element that triggered the event
*/
map(([incoming, scrollElementMapping]: [Tuple, string[]]) => {
const [event] = incoming;
return [
incoming,
scrollElementMapping.filter(
(item, index) => index !== event.mappingIndex
)
];
}),
/**
* Now perform the scroll on all other matching elements
*/
tap(([incoming, scrollElementMapping]: [Tuple, string[]]) => {
const [
event,
window,
document,
scrollProportionally
] = incoming;
scrollElementMapping
.map(selector => document.querySelector(selector))
.forEach(element => {
scrollElement(element, scrollProportionally, event);
});
})
)
).pipe(ignoreElements());
}
}
function scrollElement(element, scrollProportionally, event: IncomingPayload) {
if (scrollProportionally && element.scrollTo) {
return element.scrollTo(
0,
element.scrollHeight * event.position.proportional
); // % of y axis of scroll to px
}
return element.scrollTo(0, event.position.raw.y);
}