blob: 2c5e9cab28baca8da44c5c6666bfc2aa3ad6cbc6 (
plain) (
blame)
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
|
/** @jsx jsx */
import { jsx, css } from "@emotion/react";
import React from "react";
import colors from "../colors";
import smoothscroll from "smoothscroll-polyfill";
smoothscroll.polyfill();
const styles = css`
width: 2.5rem;
height: 2.5rem;
position: fixed;
bottom: 3rem;
right: 3rem;
background-color: ${colors.blurple};
border-radius: 50%;
opacity: 0;
transition: opacity 300ms;
:after {
display: inline-block;
content: "";
position: fixed;
bottom: 3.5rem;
right: 3.65rem;
border: solid whitesmoke;
border-width: 0.35rem 0.35rem 0 0;
padding: 0.4rem;
transform: rotate(-45deg);
}
@media (max-width: 800px) {
bottom: 1.5rem;
right: 1.5rem;
:after {
bottom: 2rem;
right: 2.15rem;
}
}
`;
let last_ref: React.RefObject<HTMLDivElement>;
class ScrollToTop extends React.Component {
constructor(props: Record<string, never>) {
super(props);
last_ref = React.createRef();
}
handleScroll(): void {
if (!last_ref.current) return;
if (window.pageYOffset > 250) {
last_ref.current.style.opacity = "1";
} else {
last_ref.current.style.opacity = "0";
}
}
componentDidMount(): void {
// Register event handler
window.addEventListener("scroll", this.handleScroll, {passive: true});
}
componentDidUpdate(): void {
// Hide previous iterations, and register handler for current one
if (last_ref.current) {
last_ref.current.style.opacity = "0";
}
window.addEventListener("scroll", this.handleScroll, {passive: true});
}
componentWillUnmount(): void {
// Unregister handler
window.removeEventListener("scroll", this.handleScroll);
}
render(): JSX.Element {
return <div css={styles} key={Date.now()} ref={last_ref} onClick={() => window.scrollTo({top: 0, behavior: "smooth"})}/>;
}
}
export default ScrollToTop;
|
