use components for non-blocking builds

packages/docs/src/asset-builder/asset-builder.ts

@@ -1,10 +1,12 @@
 import type { RequestHandler } from "express"
 import express from "express"
 import { createHash } from "node:crypto"
-import { mkdir, rm, writeFile } from "node:fs/promises"
-import { dirname, join, parse } from "node:path"
+import { mkdir, rm } from "node:fs/promises"
+import { join, parse } from "node:path"
+import { Promisable } from "type-fest"
+import { ensureWrite, normalizeAsFilePath } from "../helpers/filesystem.js"
 
-type Asset = {
+export type Asset = {
   inputFile: string
   outputFile: string
   url: string
@@ -20,8 +22,6 @@ export type AssetTransformResult = {
 }
 
 export class AssetBuilder {
-  private library = new Map<string, Asset>()
-
   private constructor(
     private cacheFolder: string,
     private transformers: AssetTransformer[],
@@ -29,19 +29,14 @@ export class AssetBuilder {
 
   static async create(cacheFolder: string, transformers: AssetTransformer[]) {
     if (process.env.NODE_ENV !== "production") {
-      await rm(cacheFolder, { recursive: true }).catch()
+      await rm(cacheFolder, { recursive: true }).catch(() => {})
     }
     await mkdir(cacheFolder, { recursive: true })
     return new AssetBuilder(cacheFolder, transformers)
   }
 
-  async build(inputFile: string | URL, name?: string): Promise<string> {
-    inputFile = normalizeAsFilePath(inputFile)
-
-    const existing = this.library.get(inputFile)
-    if (existing) {
-      return existing.url
-    }
+  async build(input: Promisable<string | URL>, name?: string): Promise<Asset> {
+    const inputFile = normalizeAsFilePath(await input)
 
     const transformResult = await this.transform(inputFile)
 
@@ -55,20 +50,8 @@ export class AssetBuilder {
     const outputFile = join(this.cacheFolder, url)
 
     await ensureWrite(outputFile, transformResult.content)
-    this.library.set(inputFile, { inputFile, outputFile, url })
 
-    return url
-  }
-
-  local(inputFile: string | URL, name?: string): string {
-    inputFile = normalizeAsFilePath(inputFile)
-
-    const asset = this.library.get(inputFile)
-    if (asset) {
-      return asset.url
-    }
-
-    throw this.build(inputFile, name)
+    return { inputFile, outputFile, url }
   }
 
   middleware(): RequestHandler {
@@ -86,12 +69,3 @@ export class AssetBuilder {
     throw new Error(`No transformers found for ${inputFile}`)
   }
 }
-
-async function ensureWrite(file: string, content: string) {
-  await mkdir(dirname(file), { recursive: true })
-  await writeFile(file, content)
-}
-
-function normalizeAsFilePath(file: string | URL) {
-  return new URL(file, "file:").pathname
-}

packages/docs/src/asset-builder/asset.tsx

@@ -0,0 +1,70 @@
+import React, { ReactNode } from "react"
+import { normalizeAsFilePath } from "../helpers/filesystem.js"
+import { useAssetBuilder } from "./asset-builder-context.js"
+import { Asset, AssetBuilder } from "./asset-builder.js"
+
+type AssetState =
+  | { status: "building"; promise: Promise<unknown> }
+  | { status: "built"; asset: Asset }
+
+const cache = new Map<string, AssetState>()
+
+function useAssetBuild(
+  cacheKey: string,
+  build: (builder: AssetBuilder) => Promise<Asset>,
+) {
+  const builder = useAssetBuilder()
+
+  const state = cache.get(cacheKey)
+  if (!state) {
+    const promise = build(builder).then((asset) => {
+      cache.set(cacheKey, { status: "built", asset })
+    })
+
+    cache.set(cacheKey, { status: "building", promise })
+    throw promise
+  }
+
+  if (state.status === "building") {
+    throw state.promise
+  }
+
+  return state.asset.url
+}
+
+export function LocalFileAsset({
+  from,
+  as: name,
+  children,
+}: {
+  from: string | URL
+  as?: string
+  children: (url: string) => ReactNode
+}) {
+  const inputFile = normalizeAsFilePath(from)
+
+  const url = useAssetBuild(inputFile, (builder) => {
+    return builder.build(inputFile, name)
+  })
+
+  return <>{children(url)}</>
+}
+
+export function ModuleAsset({
+  from,
+  as: name,
+  children,
+}: {
+  from: string
+  as?: string
+  children: (url: string) => ReactNode
+}) {
+  const cacheKey = `node:${from}`
+
+  const url = useAssetBuild(cacheKey, async (builder) => {
+    const inputFile = await import.meta.resolve!(from)
+    return await builder.build(inputFile, name)
+  })
+
+  return <>{children(url)}</>
+}

packages/docs/src/helpers/filesystem.ts

@@ -0,0 +1,11 @@
+import { mkdir, writeFile } from "node:fs/promises"
+import { dirname } from "node:path"
+
+export async function ensureWrite(file: string, content: string) {
+  await mkdir(dirname(file), { recursive: true })
+  await writeFile(file, content)
+}
+
+export function normalizeAsFilePath(file: string | URL) {
+  return new URL(file, "file:").pathname
+}

packages/docs/src/html.tsx

@@ -1,14 +1,7 @@
 import packageJson from "reacord/package.json"
 import type { ReactNode } from "react"
 import React from "react"
-import { useAssetBuilder } from "./asset-builder/asset-builder-context.js"
-
-const tailwindCssPath = new URL(
-  await import.meta.resolve!("tailwindcss/tailwind.css"),
-).pathname
-
-const alpineJs = new URL(await import.meta.resolve!("alpinejs/dist/cdn.js"))
-  .pathname
+import { LocalFileAsset, ModuleAsset } from "./asset-builder/asset.js"
 
 export function Html({
   title = "Reacord",
@@ -19,7 +12,6 @@ export function Html({
   description?: string
   children: ReactNode
 }) {
-  const assets = useAssetBuilder()
   return (
     <html lang="en" className="bg-slate-900 text-slate-100">
       <head>
@@ -38,15 +30,20 @@ export function Html({
           as="style"
           href="https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@500&family=Rubik:ital,wght@0,300;0,400;0,500;1,300;1,400;1,500&display=swap"
         />
-        <link rel="stylesheet" href={assets.local(tailwindCssPath)} />
-        <link
-          rel="stylesheet"
-          href={assets.local(new URL("ui/prism-theme.css", import.meta.url))}
-        />
+
+        <ModuleAsset from="tailwindcss/tailwind.css">
+          {(url) => <link rel="stylesheet" href={url} />}
+        </ModuleAsset>
+
+        <LocalFileAsset from={new URL("ui/prism-theme.css", import.meta.url)}>
+          {(url) => <link rel="stylesheet" href={url} />}
+        </LocalFileAsset>
 
         <title>{title}</title>
 
-        <script defer src={assets.local(alpineJs, "alpine")} />
+        <ModuleAsset from="alpinejs/dist/cdn.js" as="alpine">
+          {(url) => <script defer src={url} />}
+        </ModuleAsset>
       </head>
       <body>{children}</body>
     </html>