feat: support static data loaders

package.json

@@ -90,6 +90,7 @@
     "@types/koa-static": "^4.0.1",
     "@types/lru-cache": "^5.1.0",
     "@types/markdown-it": "^12.0.1",
+    "@types/micromatch": "^4.0.2",
     "@types/node": "^15.6.1",
     "@types/polka": "^0.5.3",
     "chalk": "^4.1.1",
@@ -102,6 +103,7 @@
     "esbuild": "^0.13.4",
     "escape-html": "^1.0.3",
     "execa": "^5.0.0",
+    "fast-glob": "^3.2.7",
     "fs-extra": "^10.0.0",
     "globby": "^11.0.3",
     "gray-matter": "^4.0.3",
@@ -114,6 +116,7 @@
     "markdown-it-container": "^3.0.0",
     "markdown-it-emoji": "^2.0.0",
     "markdown-it-table-of-contents": "^0.5.2",
+    "micromatch": "^4.0.4",
     "minimist": "^1.2.5",
     "npm-run-all": "^4.1.5",
     "ora": "^5.4.0",

src/node/plugin.ts

@@ -8,6 +8,7 @@ import {
 import { DIST_CLIENT_PATH, APP_PATH, SITE_DATA_REQUEST_PATH } from './alias'
 import { slash } from './utils/slash'
 import { OutputAsset, OutputChunk } from 'rollup'
+import { staticDataPlugin } from './staticDataPlugin'
 
 const hashRE = /\.(\w+)\.js$/
 const staticInjectMarkerRE =
@@ -273,5 +274,10 @@ export function createVitePressPlugin(
     }
   }
 
-  return [vitePressPlugin, vuePlugin, ...(userViteConfig?.plugins || [])]
+  return [
+    vitePressPlugin,
+    vuePlugin,
+    ...(userViteConfig?.plugins || []),
+    staticDataPlugin
+  ]
 }

src/node/staticDataPlugin.ts

@@ -0,0 +1,116 @@
+// TODO figure out why it causes full page reload
+
+import { Plugin, ViteDevServer, loadConfigFromFile, normalizePath } from 'vite'
+import { dirname, relative } from 'path'
+import { isMatch } from 'micromatch'
+
+const loaderMatch = /\.data\.(j|t)s$/
+
+let server: ViteDevServer
+
+interface LoaderModule {
+  base: string
+  pattern: string | undefined
+  loader: () => any
+}
+
+const idToLoaderModulesMap: Record<string, LoaderModule | undefined> =
+  Object.create(null)
+
+// During build, the load hook will be called on the same file twice
+// once for client and once for server build. Not only is this wasteful, it
+// also leads to a race condition in loadConfigFromFile() that results in an
+// fs unlink error. So we reuse the same Promise during build to avoid double
+// loading.
+let idToPendingPromiseMap: Record<string, Promise<string> | undefined> =
+  Object.create(null)
+let isBuild = false
+
+export const staticDataPlugin: Plugin = {
+  name: 'vitepress:data',
+
+  configResolved(config) {
+    isBuild = config.command === 'build'
+  },
+
+  configureServer(_server) {
+    server = _server
+  },
+
+  async load(id) {
+    if (loaderMatch.test(id)) {
+      let _resolve: ((res: any) => void) | undefined
+      if (isBuild) {
+        if (idToPendingPromiseMap[id]) {
+          return idToPendingPromiseMap[id]
+        }
+        idToPendingPromiseMap[id] = new Promise((r) => {
+          _resolve = r
+        })
+      }
+
+      const base = dirname(id)
+      let pattern: string | undefined
+      let loader: () => any
+
+      const existing = idToLoaderModulesMap[id]
+      if (existing) {
+        ;({ pattern, loader } = existing)
+      } else {
+        // use vite's load config util as a away to load Node.js file with
+        // TS & native ESM support
+        const loaderModule = (await loadConfigFromFile({} as any, id))
+          ?.config as any
+        pattern = loaderModule.watch
+        if (pattern && pattern.startsWith('./')) {
+          pattern = pattern.slice(2)
+        }
+        loader = loaderModule.load
+      }
+
+      // load the data
+      const data = await loader()
+
+      // record loader module for HMR
+      if (server) {
+        idToLoaderModulesMap[id] = { base, pattern, loader }
+      }
+
+      const result = `export const data = JSON.parse(${JSON.stringify(
+        JSON.stringify(data)
+      )})`
+
+      if (_resolve) _resolve(result)
+      return result
+    }
+  },
+
+  transform(_code, id) {
+    if (server && loaderMatch.test(id)) {
+      // register this module as a glob importer
+      const { base, pattern } = idToLoaderModulesMap[id]!
+      ;(server as any)._globImporters[id] = {
+        module: server.moduleGraph.getModuleById(id),
+        importGlobs: [{ base, pattern }]
+      }
+    }
+    return null
+  },
+
+  handleHotUpdate(ctx) {
+    for (const id in idToLoaderModulesMap) {
+      const { base, pattern } = idToLoaderModulesMap[id]!
+      const isLoaderFile = normalizePath(ctx.file) === id
+      if (isLoaderFile) {
+        // invalidate loader file
+        delete idToLoaderModulesMap[id]
+      }
+      if (
+        isLoaderFile ||
+        (pattern && isMatch(relative(base, ctx.file), pattern))
+      ) {
+        ctx.modules.push(server.moduleGraph.getModuleById(id)!)
+      }
+    }
+  }
+}