test: validate canonical exports after inline transform (#5699)

Author: kuhe

.gitignore

@@ -40,6 +40,7 @@ codegen/sdk-codegen/smithy-build-*.json
 */out/
 */*/out/
 workspace
+./scripts/compilation/tmp/*.mjs
 
 .turbo
 coverage

scripts/compilation/Inliner.js

@@ -48,6 +48,7 @@ module.exports = class Inliner {
   async tsc() {
     await spawnProcess("yarn", ["tsc", "-p", "tsconfig.cjs.json"], { cwd: this.packageDirectory });
     console.log("Finished recompiling ./dist-cjs in " + this.package);
+    this.canonicalExports = Object.keys(require(this.outfile));
     return this;
   }
 
@@ -57,6 +58,7 @@ module.exports = class Inliner {
    */
   async discoverVariants() {
     if (this.bailout) {
+      console.log("Inliner bailout.");
       return this;
     }
     this.variantEntries = Object.entries(this.pkgJson["react-native"] ?? {});
@@ -338,6 +340,17 @@ module.exports = class Inliner {
           " were not found in the index."
       );
     }
+
+    // check ESM compat.
+    const tmpFileContents = this.canonicalExports
+      .filter((sym) => !sym.includes(":"))
+      .map((sym) => `import { ${sym} } from "${this.pkgJson.name}";`)
+      .join("\n");
+    fs.writeFileSync(path.join(__dirname, "tmp", this.package + ".mjs"), tmpFileContents, "utf-8");
+    await spawnProcess("node", [path.join(__dirname, "tmp", this.package + ".mjs")]);
+    console.log("ESM compatibility verified.");
+    fs.rmSync(path.join(__dirname, "tmp", this.package + ".mjs"));
+
     return this;
   }
 };

scripts/compilation/tmp/.gitignore

@@ -0,0 +1 @@
+*.mjs