ancientstraits · March 18, 2025 17:10 · Mar 18, 2025
diff --git a/genImportMap.js b/genImportMap.js
@@ -0,0 +1,64 @@
+import fs from 'node:fs'
+
+const imports = [
+    { alias: 'firebase/app',      path: '@firebase/app' },
+    { alias: 'firebase/auth',     path: '@firebase/auth' },
+    { alias: 'firebase/database', path: '@firebase/database' }
+]
+
+if (!fs.existsSync('node_modules')) {
+    console.error('Please run `npm i`')
+    process.exit(1)
+}
+
+const pkgJson = path => JSON.parse(fs.readFileSync(`${path}/package.json`).toString())
+const getMainPath = pkg => pkg.browser || pkg.module || undefined
+function getEntryPoint(pkg, path) {
+    const mainPath = getMainPath(pkg)
+    if (mainPath === undefined) return undefined
+
+    const entryPoint = `./node_modules/${path}/${mainPath}`
+    if (!fs.existsSync(entryPoint)) {
+        console.error(`${entryPoint} is not a real file`)
+        process.exit(1)
+    }
+
+    return entryPoint
+}
+
+const importMap = {
+    imports: {},
+    // scopes:  {}
+}
+const deps = new Set()
+
+for (const {alias, path} of imports) {
+    const pkg = pkgJson(`node_modules/${path}`)
+
+    Object.keys(pkg.dependencies).forEach(dep => deps.add(dep))
+    // deps.add(path)
+
+    const entryPoint = getEntryPoint(pkg, path)
+    importMap.imports[alias] = entryPoint
+    importMap.imports[path]  = entryPoint
+}
+
+for (const dep of deps) {
+    const pkg = pkgJson(`node_modules/${dep}`)
+
+    const entryPoint = getEntryPoint(pkg, dep)
+    importMap.imports[dep] = entryPoint
+}
+
+const indent = '    '
+
+const stringified = JSON.stringify(importMap, undefined, 4)
+    .split('\n')
+    .map(line => `${indent}${indent}${line}`)
+    .join('\n')
+
+const importmapTag = /<script type="importmap">[\s\S]*?<\/script>/
+
+const indexHtml = fs.readFileSync('index.html').toString()
+const modified = indexHtml.replace(importmapTag, `<script type="importmap">\n${stringified}\n${indent}</script>`)
+fs.writeFileSync('index.html', modified)