2021-02-11 21:31:41 +08:00

130 lines
3.7 KiB
JavaScript

'use strict'
/**
* Module dependencies.
*/
const { EventEmitter } = require('events')
const { getOptions } = require('loader-utils')
const { fs, path, hash, parseFrontmatter, inferTitle, extractHeaders } = require('@vuepress/shared-utils')
const LRU = require('lru-cache')
const md = require('@vuepress/markdown')
const cache = new LRU({ max: 1000 })
const devCache = new LRU({ max: 1000 })
/**
* Expose markdown loader.
*/
module.exports = function (src) {
const isProd = process.env.NODE_ENV === 'production'
const isServer = this.target === 'node'
const options = getOptions(this)
const loader = Object.create(this)
const { sourceDir, extractHeaders: extractHeadersPattern = ['h2', 'h3'] } = options
let { markdown } = options
if (!markdown) {
markdown = md()
}
// we implement a manual cache here because this loader is chained before
// vue-loader, and will be applied on the same file multiple times when
// selecting the individual blocks.
const file = this.resourcePath
const key = hash(file + src)
const cached = cache.get(key)
if (cached && (isProd || /\?vue/.test(this.resourceQuery))) {
return cached
}
const frontmatter = parseFrontmatter(src)
const content = frontmatter.content
if (!isProd && !isServer) {
const inferredTitle = inferTitle(frontmatter.data, frontmatter.content)
const headers = extractHeaders(content, extractHeadersPattern, markdown)
delete frontmatter.content
// diff frontmatter and title, since they are not going to be part of the
// returned component, changes in frontmatter do not trigger proper updates
const cachedData = devCache.get(file)
if (cachedData && (
cachedData.inferredTitle !== inferredTitle
|| JSON.stringify(cachedData.frontmatterData) !== JSON.stringify(frontmatter.data)
|| headersChanged(cachedData.headers, headers)
)) {
// frontmatter changed... need to do a full reload
module.exports.frontmatterEmitter.emit('update', file)
}
devCache.set(file, {
headers,
frontmatterData: frontmatter.data,
inferredTitle
})
}
// the render method has been augmented to allow plugins to
// register data during render
const {
html,
data: { hoistedTags, links },
dataBlockString
} = markdown.render(content, {
loader,
frontmatter: frontmatter.data,
relativePath: path.relative(sourceDir, file).replace(/\\/g, '/')
})
// check if relative links are valid
links && links.forEach(link => {
link = decodeURIComponent(link)
const shortname = link
.replace(/#.*$/, '')
.replace(/\.html$/, '.md')
const filename = shortname
.replace(/\/$/, '/README.md')
.replace(/^\//, sourceDir + '/')
const altname = shortname
.replace(/\/$/, '/index.md')
.replace(/^\//, sourceDir + '/')
const dir = path.dirname(this.resourcePath)
const file = path.resolve(dir, filename)
const altfile = altname !== filename ? path.resolve(dir, altname) : null
if (!fs.existsSync(file) && (!altfile || !fs.existsSync(altfile))) {
this.emitWarning(
new Error(
`\nFile for relative link "${link}" does not exist.\n`
+ `(Resolved file: ${file})\n`
)
)
}
})
const res = (
`<template>\n`
+ `<ContentSlotsDistributor :slot-key="$parent.slotKey">${html}</ContentSlotsDistributor>\n`
+ `</template>\n`
+ (hoistedTags || []).join('\n')
+ `\n${dataBlockString}\n`
)
cache.set(key, res)
return res
}
function headersChanged (a, b) {
if (a.length !== b.length) return true
return a.some((h, i) => (
h.title !== b[i].title
|| h.level !== b[i].level
))
}
module.exports.frontmatterEmitter = new EventEmitter()