fix: ensure CSS modules attached to dynamic import modules are includ…

…ed in build output

- add implementation for BabelTarget.getTargetFromGroup()
- add method to determine the original asset name from a targeted asset name

fixes #40

src/babel-target.ts

@@ -108,6 +108,10 @@ export class BabelTarget implements BabelTargetInfo {
     return this.tagAssetsWithKey ? `${name}.${this.key}` : name
   }
 
+  public getUntargetedAssetName(targetedAssetName: string): string {
+    return this.tagAssetsWithKey ? targetedAssetName : targetedAssetName.replace(`.${this.key}`, '')
+  }
+
   public getTargetedRequest(request: string): string {
     const tag = `babel-target=${this.key}`
     if (request.includes(tag)) {
@@ -165,8 +169,13 @@ export class BabelTarget implements BabelTargetInfo {
     return BabelTarget.getTargetFromModule(entrypoint.runtimeChunk.entryModule)
   }
 
-  // eslint-disable-next-line
   public static getTargetFromGroup(group: ChunkGroup): BabelTarget {
+    for (const origin of group.origins) {
+      const target = BabelTarget.getTargetFromModule(origin.module)
+      if (target) {
+        return target
+      }
+    }
     return undefined
   }
 
@@ -175,6 +184,13 @@ export class BabelTarget implements BabelTargetInfo {
       return BabelTarget.getTargetFromModule(chunk.entryModule)
     }
 
+    for (const group of chunk.groupsIterable) {
+      const target = BabelTarget.getTargetFromGroup(group)
+      if (target) {
+        return target
+      }
+    }
+
     return undefined
   }
 

src/normalize.css.chunks.plugin.ts

@@ -59,7 +59,7 @@ export class NormalizeCssChunksPlugin implements Plugin {
 
       // get the original (untagged) name of the entry module so we can correctly
       // attribute any contained CSS modules to the entry
-      const name = this.findEntryName(chunk)
+      const name = this.findEntryName(chunk, target)
 
       // track the original entry names to use later
       if (!cssModules[name]) {
@@ -104,13 +104,22 @@ export class NormalizeCssChunksPlugin implements Plugin {
     })
   }
 
-  private findEntryName(chunk: Chunk): string {
+  private findEntryName(chunk: Chunk, target: BabelTarget): string {
     const entry = this.findEntryModule(chunk)
-    if (entry) {
-      return entry.reasons[0].dependency.originalName
+    if (!entry) {
+      throw new Error(`Could not determine entry module for chunk ${chunk.name}`)
+    }
+    const originalName = entry.reasons[0].dependency.originalName
+    if (originalName) {
+      return originalName
     }
 
-    throw new Error(`Could not determine entry module for chunk ${chunk.name}`)
+    if (target && chunk.name) {
+      // modules from dynamic imports don't get originalName, so just guess based on the targeted asset name
+      // TODO: can we override the default ContextElementDependency factory, similar to the entry dependencies?
+      //   this could allow setting originalName, but could also cause blind targeting to be more complicated
+      return target.getUntargetedAssetName(chunk.name)
+    }
   }
 
   private findEntryModule(chunk: Chunk): Module {