fix: better compatible with webpack v4/v5 (#52)

.changeset/dirty-olives-relate.md

@@ -0,0 +1,5 @@
+---
+"react-server-renderer": patch
+---
+
+fix: better compatible with webpack v4/v5

.nvmrc

@@ -0,0 +1 @@
+lts/*

src/webpack-plugin/server.ts

@@ -38,14 +38,14 @@ export class ReactSSRServerPlugin implements WebpackPluginInstance {
 
       const entry = entryAssets[0]
       // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
-      if (!entry || typeof entry !== 'string') {
+      if (!entry) {
         throw new Error(
           `Entry "${entryName}" not found. Did you specify the correct entry option?`,
         )
       }
 
       const bundle = {
-        entry,
+        entry: typeof entry === 'string' ? entry : entry.name,
         files: {} as Record<string, Buffer | string>,
         maps: {} as Record<string, unknown>,
       }

src/webpack-plugin/util.ts

@@ -9,18 +9,21 @@ export const warn = (msg: string) => console.error(red(`${prefix} ${msg}\n`))
 export const tip = (msg: string) => console.log(yellow(`${prefix} ${msg}\n`))
 
 export const validate = (compiler: Compiler) => {
-  if (compiler.options.target !== 'node') {
+  const { externals, output, target } = compiler.options
+
+  if (target !== 'node') {
     warn('webpack config `target` should be "node".')
   }
 
   if (
+    output.library?.type !== 'commonjs2' &&
     // @ts-expect-error -- compatibility
-    compiler.options.output.libraryTarget !== 'commonjs2'
+    output.libraryTarget !== 'commonjs2'
   ) {
     warn('webpack config `output.libraryTarget` should be "commonjs2".')
   }
 
-  if (!compiler.options.externals) {
+  if (!externals) {
     tip(
       'It is recommended to externalize dependencies in the server build for ' +
         'better build performance.',