未处理的拒绝(类型错误)：无法读取未定义的属性'current'

Question

我有一个使用谷歌地图api的gatsby应用程序。我正在加载useRef和useEffect来加载地图。useRef返回一个可变ref对象，该对象的.current属性已初始化为传递的参数(initialValue(。返回的对象将在组件的整个生存期内持续存在。这是我的代码：

import React, { useRef, useEffect } from "react"
import MapMarker from "../assets/images/logos/map-marker.png"
const Map = () => {

const map = useRef(null)
useEffect(()=>{
if(typeof window !== "undefined"){
window.initMap = function() {
const map = new window.google.maps.Map(map.current, {
center: {
lat: 142.1463554,
lng: 121.5245996
},
zoom: 10,
styles: [{"featureType":"water","elementType":"geometry","stylers":[{"color":"#d3d3d3"},{"lightness":50}]},{"featureType":"landscape","elementType":"geometry","stylers":[{"color":"#ffffff"},{"lightness":20}]},{"featureType":"road.highway","elementType":"geometry.fill","stylers":[{"color":"#ffffff"},{"lightness":17}]},{"featureType":"road.highway","elementType":"geometry.stroke","stylers":[{"color":"#ffffff"},{"lightness":29},{"weight":0.2}]},{"featureType":"road.arterial","elementType":"geometry","stylers":[{"color":"#ffffff"},{"lightness":18}]},{"featureType":"road.local","elementType":"geometry","stylers":[{"color":"#ffffff"},{"lightness":16}]},{"featureType":"poi","elementType":"geometry","stylers":[{"color":"#f5f5f5"},{"lightness":21}]},{"featureType":"poi.park","elementType":"geometry","stylers":[{"color":"#dedede"},{"lightness":21}]},{"elementType":"labels.text.stroke","stylers":[{"visibility":"on"},{"color":"#ffffff"},{"lightness":16}]},{"elementType":"labels.text.fill","stylers":[{"saturation":50},{"color":"#000000"},{"lightness":40}]},{"elementType":"labels.icon","stylers":[{"visibility":"off"}]},{"featureType":"transit","elementType":"geometry","stylers":[{"color":"#f2f2f2"},{"lightness":19}]},{"featureType":"administrative","elementType":"geometry.fill","stylers":[{"color":"#4c4c4c"},{"lightness":20}]},{"featureType":"administrative","elementType":"geometry.stroke","stylers":[{"color":"#4c4c4c"},{"lightness":17},{"weight":1.2}]}]
})
new window.google.maps.Marker({
position: { lat: 112.1463554, lng: 130.5245993 },
icon: MapMarker,
animation: window.google.maps.Animation.BOUNCE,
map: map
});
}
}
return () => map.current = null
}, [])


return (
<div id="map-container" data-aos="fade-up">
<div className="container-fluid">
<div className="row">
<div className="col-lg-12 col-12 pl-0 pr-0">
<div className="google-map">
<div id="map" ref={map}></div>
</div>
</div>
</div>
</div>
</div>
)
}
export default Map

当我加载我的gatsby应用程序时，它返回：

Unhandled Rejection (TypeError): Cannot read property 'current' of undefined
window.initMap
C:/Users/Read/Desktop/gatsby/src/components/Map.js:12
9 | 
10 |    if(typeof window !== "undefined"){
11 |      window.initMap = function() {
> 12 |   const map = new window.google.maps.Map(map.current, {
13 |        center: {
14 |            lat: 11.1463554,
15 |            lng: 110.5245996

知道怎么解决这个问题吗？请帮忙！

Answer 1

访问引用时存在命名问题，因为map和引用的名称相同，所以会因为作用域而导致此问题。更改为：

import React, { useRef, useEffect } from "react"
import MapMarker from "../assets/images/logos/map-marker.png"

const Map = () => {

const mapRef = useRef(null)

useEffect(()=>{

if(typeof window !== "undefined"){
window.initMap = function() {
const map = new window.google.maps.Map(mapRef.current, {
center: {
lat: 11.1463554,
lng: 110.5245996
},
zoom: 10,
styles: [{"featureType":"water","elementType":"geometry","stylers":[{"color":"#d3d3d3"},{"lightness":50}]},{"featureType":"landscape","elementType":"geometry","stylers":[{"color":"#ffffff"},{"lightness":20}]},{"featureType":"road.highway","elementType":"geometry.fill","stylers":[{"color":"#ffffff"},{"lightness":17}]},{"featureType":"road.highway","elementType":"geometry.stroke","stylers":[{"color":"#ffffff"},{"lightness":29},{"weight":0.2}]},{"featureType":"road.arterial","elementType":"geometry","stylers":[{"color":"#ffffff"},{"lightness":18}]},{"featureType":"road.local","elementType":"geometry","stylers":[{"color":"#ffffff"},{"lightness":16}]},{"featureType":"poi","elementType":"geometry","stylers":[{"color":"#f5f5f5"},{"lightness":21}]},{"featureType":"poi.park","elementType":"geometry","stylers":[{"color":"#dedede"},{"lightness":21}]},{"elementType":"labels.text.stroke","stylers":[{"visibility":"on"},{"color":"#ffffff"},{"lightness":16}]},{"elementType":"labels.text.fill","stylers":[{"saturation":50},{"color":"#000000"},{"lightness":40}]},{"elementType":"labels.icon","stylers":[{"visibility":"off"}]},{"featureType":"transit","elementType":"geometry","stylers":[{"color":"#f2f2f2"},{"lightness":19}]},{"featureType":"administrative","elementType":"geometry.fill","stylers":[{"color":"#4c4c4c"},{"lightness":20}]},{"featureType":"administrative","elementType":"geometry.stroke","stylers":[{"color":"#4c4c4c"},{"lightness":17},{"weight":1.2}]}]
})

new window.google.maps.Marker({
position: { lat: 112.1463554, lng: 130.5245993 },
icon: MapMarker,
animation: window.google.maps.Animation.BOUNCE,
map: map
});
}

}

return () => mapRef.current = null

}, [])


return (
<div id="map-container" data-aos="fade-up">
<div className="container-fluid">
<div className="row">
<div className="col-lg-12 col-12 pl-0 pr-0">
<div className="google-map">
<div id="map" ref={mapRef}></div>
</div>
</div>
</div>
</div>
</div>
)
}
export default Map