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
|
// @flow
import React, { Component } from 'react';
import type { Point2d } from '../types';
const CLICK_TIMEOUT = 1000;
const MOVE_THRESHOLD = 10;
export default class Switch extends Component {
props: {
isOn: boolean;
onChange: ?((isOn: boolean) => void);
}
defaultProps = {
isOn: false
}
ref: ?HTMLInputElement;
onRef = (e: HTMLInputElement) => this.ref = e;
state = {
isTracking: false,
ignoreChange: false,
initialPos: (null: ?Point2d),
startTime: (null: ?number)
}
handleMouseDown = (e: MouseEvent) => {
const { pageX: x, pageY: y } = e;
this.setState({
isTracking: true,
initialPos: { x, y },
startTime: e.timeStamp
});
}
handleMouseMove = (e: MouseEvent) => {
if(!this.state.isTracking) {
return;
}
const inputElement = this.ref;
const { x: x0 } = this.state.initialPos;
const { pageX: x, pageY: y } = e;
const dx = Math.abs(x0 - x);
if(dx < MOVE_THRESHOLD) {
return;
}
const isOn = !!this.props.isOn;
let nextOn = isOn;
if(x < x0 && isOn) {
nextOn = false;
} else if(x > x0 && !isOn) {
nextOn = true;
}
if(isOn !== nextOn) {
this.setState({
initialPos: { x, y },
ignoreChange: true
});
if(inputElement) {
inputElement.checked = nextOn;
}
this.notify(nextOn);
}
}
handleMouseUp = () => {
if(this.state.isTracking) {
this.setState({
isTracking: false,
initialPos: null
});
}
}
handleChange = (e: Event) => {
const startTime = this.state.startTime;
const eventTarget = e.target;
if(typeof(startTime) !== 'number') {
throw new Error('startTime must be a number.');
}
if(!(eventTarget instanceof HTMLInputElement)) {
throw new Error('e.target must be an instance of HTMLInputElement.');
}
const dt = e.timeStamp - startTime;
if(this.state.ignoreChange) {
this.setState({ ignoreChange: false });
e.preventDefault();
} else if(dt > CLICK_TIMEOUT) {
e.preventDefault();
} else {
this.notify(eventTarget.checked);
}
}
notify(isOn: boolean) {
const onChange = this.props.onChange;
if(onChange) {
onChange(isOn);
}
}
componentDidMount() {
document.addEventListener('mousemove', this.handleMouseMove);
document.addEventListener('mouseup', this.handleMouseUp);
}
componentWillUnmount() {
document.removeEventListener('mousemove', this.handleMouseMove);
document.removeEventListener('mouseup', this.handleMouseUp);
}
render(): React.Element<*> {
return (
<input type="checkbox" ref={ this.onRef } className="switch" checked={ this.props.isOn }
onMouseDown={ this.handleMouseDown }
onChange={ this.handleChange } />
);
}
}
|
