正在获取未定义的值.Javascript/React/映射

Question

为什么我得到"无法读取null"的属性"cityLocation"；关于createSiteMap函数？只有｛propertyOwner｝属性具有未定义的值。

但是，我能够控制台.log(propertyOwner(，并且我正在获取值。以下是控制台日志的结果：

2 608432995a21dc4d28bc8748 sg

4 608434915a21dc4d28bc8762我的

2 608fc2e15a21dc4d28bc886f jp

2 60937f6美国

import { api } from '@helpers/api'
import { BASE_URL } from '@helpers/config'
import Slugify from 'slugify'
import { generateAuthHeaders } from '@helpers/authHeaders'
import { API_TOKEN } from '@helpers/config'
const url = BASE_URL
const createSitemap = (listings, date) => `<?xml version="1.0" encoding="UTF-8"?>
<sitemapindex xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 
http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xmlns="http://www.sitemaps.org/schemas/sitemap/0.9" 
xmlns:xhtml="http://www.w3.org/1999/xhtml">

${listings
.map(({ id, propertyOwner, listingName }) => {
return `
<sitemap>
<loc>${`${url}rooms/for-rent/${id}/${Slugify(propertyOwner.cityLocation, { <<<--------------
lower: true,
strict: true,
})}/rentalbee-at-${Slugify(propertyOwner.codeName, {
lower: true,
strict: true,
})}/room-for-${Slugify(listingName, {
lower: true,
strict: true,
})}`}</loc>
<lastmod>${date}</lastmod>
</sitemap>
`
})
.join('')}
</sitemapindex>
`
class SitemapId extends React.Component {
static async getInitialProps({ res, query }) {
const allRooms = await api.get(
'/listings',
{
headers: generateAuthHeaders(null, 'application/json', API_TOKEN),
},
{ params: { page: query.id } }
)
const date = new Date().toISOString().split('T')[0]
allRooms.data.listings.map(({ listingName, id, propertyOwner }) =>
console.log(listingName, id, propertyOwner.cityLocation)  <<---------------------
)
res.setHeader('Content-Type', 'text/xml')
res.write(createSitemap(allRooms.data.listings, date))
res.end()
}
}
export default SitemapId

Answer 1

而不是这个：

console.log(listingName, id, propertyOwner.cityLocation)  <<---------------------
)

试着测试这个

console.log(listingName, id, propertyOwner[id].cityLocation)

线索：最后一个参数与地图功能中的原始对象相同

propertyOwner <=> allRooms.data.listings