use-battery

1import { useEffect, useState } from 'react'
2 
3type BatteryEventName =
4  | 'chargingchange'
5  | 'chargingtimechange'
6  | 'dischargingtimechange'
7  | 'levelchange'
8 
9const BATTERY_EVENTS: BatteryEventName[] = [
10  'chargingchange',
11  'chargingtimechange',
12  'dischargingtimechange',
13  'levelchange',
14]
15 
16const DEFAULT_BATTERY_STATE = {
17  charging: false,
18  chargingTime: 0,
19  dischargingTime: 0,
20  level: 1,
21}
22 
23interface BatteryManagerLike extends EventTarget {
24  charging: boolean
25  chargingTime: number
26  dischargingTime: number
27  level: number
28}
29 
30interface NavigatorWithBattery extends Navigator {
31  getBattery?: () => Promise<BatteryManagerLike>
32}
33 
34export interface UseBatteryState {
35  isSupported: boolean
36  charging: boolean
37  chargingTime: number
38  dischargingTime: number
39  level: number
40}
41 
42function isBatterySupported(): boolean {
43  if (typeof navigator === 'undefined') {
44    return false
45  }
46 
47  const nav = navigator as NavigatorWithBattery
48  return typeof nav.getBattery === 'function'
49}
50 
51/**
52 * Monitor the current battery information using the Battery Status API.
53 *
54 * @see https://developer.mozilla.org/en-US/docs/Web/API/Battery_Status_API
55 * @returns Current battery state and support flag.
56 */
57export function useBattery(): UseBatteryState {
58  const [state, setState] = useState<UseBatteryState>(() => {
59    const isSupported = isBatterySupported()
60 
61    return {
62      isSupported,
63      ...DEFAULT_BATTERY_STATE,
64    }
65  })
66 
67  useEffect(() => {
68    if (!state.isSupported) {
69      return
70    }
71 
72    const nav = navigator as NavigatorWithBattery
73    let battery: BatteryManagerLike | null = null
74    let disposed = false
75 
76    const updateBatteryState = () => {
77      if (!battery || disposed) {
78        return
79      }
80 
81      setState({
82        isSupported: true,
83        charging: battery.charging,
84        chargingTime: battery.chargingTime,
85        dischargingTime: battery.dischargingTime,
86        level: battery.level,
87      })
88    }
89 
90    void nav
91      .getBattery?.()
92      .then((batteryManager) => {
93        if (disposed) {
94          return
95        }
96 
97        battery = batteryManager
98        updateBatteryState()
99 
100        BATTERY_EVENTS.forEach((eventName) => {
101          batteryManager.addEventListener(eventName, updateBatteryState)
102        })
103      })
104      .catch(() => {
105        // Keep default values when runtime access fails.
106      })
107 
108    return () => {
109      disposed = true
110 
111      if (!battery) {
112        return
113      }
114 
115      BATTERY_EVENTS.forEach((eventName) => {
116// … truncated