Rename .mjs files to .js (#14605)

scripts/build/esbuild-plugins/evaluate.js

@@ -0,0 +1,38 @@
+import createEsmUtils from "esm-utils";
+import serialize from "serialize-javascript";
+import { isValidIdentifier } from "@babel/types";
+
+const { importModule } = createEsmUtils(import.meta);
+
+export default function esbuildPluginEvaluate() {
+  return {
+    name: "evaluate",
+    setup(build) {
+      const { format } = build.initialOptions;
+
+      build.onLoad({ filter: /\.evaluate\.c?js$/ }, async ({ path }) => {
+        const module = await importModule(path);
+        const text = Object.entries(module)
+          .map(([specifier, value]) => {
+            value = serialize(value, { space: 2 });
+
+            if (specifier === "default") {
+              return format === "cjs"
+                ? `module.exports = ${value};`
+                : `export default ${value};`;
+            }
+
+            if (!isValidIdentifier(specifier)) {
+              throw new Error(`${specifier} is not a valid specifier`);
+            }
+
+            return format === "cjs"
+              ? `exports.${specifier} = ${value};`
+              : `export const ${specifier} = ${value};`;
+          })
+          .join("\n");
+        return { contents: text };
+      });
+    },
+  };
+}