javascript - js中的这个排序功能是如何工作的?
问题描述
在Next.js站点(此处为https://nextjs.org/learn/basics/data-fetching/implement-getstaticprops)中,此示例:
import path from 'path'
import matter from 'gray-matter'
const postsDirectory = path.join(process.cwd(), 'posts')
export function getSortedPostsData() {
// Get file names under /posts
const fileNames = fs.readdirSync(postsDirectory)
const allPostsData = fileNames.map(fileName => {
// Remove ".md" from file name to get id
const id = fileName.replace(/\.md$/, '')
// Read markdown file as string
const fullPath = path.join(postsDirectory, fileName)
const fileContents = fs.readFileSync(fullPath, 'utf8')
// Use gray-matter to parse the post metadata section
const matterResult = matter(fileContents)
// Combine the data with the id
return {
id,
...matterResult.data
}
})
// Sort posts by date
return allPostsData.sort(({ date: a }, { date: b }) => {
if (a < b) {
return 1
} else if (a > b) {
return -1
} else {
return 0
}
})
}
在此示例中,函数getSortedPostsData()的返回值是allPostsData的排序列表。帖子按日期排序。
我的问题是数组是如何排序的?
排序函数有两个参数{date:a} , {date:b}。它是否会自动将参数转换为日期对象,因为a.date 和 b.date是字符串