work

Author: dmail

dist/build/build.js

@@ -8360,6 +8360,12 @@ const jsenvPluginImportMetaCss = () => {
           return null;
         }
         if (urlInfo.context.build) {
+          if (hasModuleScopeAssignment(urlInfo.contentAst)) {
+            urlInfo.contentSideEffects.push({
+              has: true,
+              reason: "import.meta.css assigned at module scope",
+            });
+          }
           const packageName = urlInfo.packageName;
           const packageDirectoryUrl =
             urlInfo.packageDirectoryUrl || urlInfo.context.rootDirectoryUrl;
@@ -8403,6 +8409,28 @@ const jsenvPluginImportMetaCss = () => {
   };
 };
 
+// A stylesheet assigned at module scope is adopted when the module runs: that
+// assignment IS the module's side effect. It has to be told, because a
+// package.json "sideEffects" list is authoritative once it exists — a module
+// it does not name is dropped whole when it is imported for nothing else, and
+// its css silently leaves the build.
+const hasModuleScopeAssignment = (ast) => {
+  for (const node of ast.body) {
+    if (node.type !== "ExpressionStatement") {
+      continue;
+    }
+    const { expression } = node;
+    if (
+      expression.type === "AssignmentExpression" &&
+      expression.operator === "=" &&
+      getImportMetaPropertyName(expression.left) === "css"
+    ) {
+      return true;
+    }
+  }
+  return false;
+};
+
 const babelPluginRewriteImportMetaCssAssignment = (
   { types: t },
   { relativeUrl },

dist/start_dev_server/start_dev_server.js

@@ -6179,6 +6179,12 @@ const jsenvPluginImportMetaCss = () => {
           return null;
         }
         if (urlInfo.context.build) {
+          if (hasModuleScopeAssignment(urlInfo.contentAst)) {
+            urlInfo.contentSideEffects.push({
+              has: true,
+              reason: "import.meta.css assigned at module scope",
+            });
+          }
           const packageName = urlInfo.packageName;
           const packageDirectoryUrl =
             urlInfo.packageDirectoryUrl || urlInfo.context.rootDirectoryUrl;
@@ -6222,6 +6228,28 @@ const jsenvPluginImportMetaCss = () => {
   };
 };
 
+// A stylesheet assigned at module scope is adopted when the module runs: that
+// assignment IS the module's side effect. It has to be told, because a
+// package.json "sideEffects" list is authoritative once it exists — a module
+// it does not name is dropped whole when it is imported for nothing else, and
+// its css silently leaves the build.
+const hasModuleScopeAssignment = (ast) => {
+  for (const node of ast.body) {
+    if (node.type !== "ExpressionStatement") {
+      continue;
+    }
+    const { expression } = node;
+    if (
+      expression.type === "AssignmentExpression" &&
+      expression.operator === "=" &&
+      getImportMetaPropertyName(expression.left) === "css"
+    ) {
+      return true;
+    }
+  }
+  return false;
+};
+
 const babelPluginRewriteImportMetaCssAssignment = (
   { types: t },
   { relativeUrl },

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@jsenv/core",
-  "version": "41.4.26",
+  "version": "41.4.27",
   "type": "module",
   "description": "Tool to develop, test and build js projects",
   "repository": {