diff --git a/build.js b/build.js
index f16e3a9..39becb4 100644
--- a/build.js
+++ b/build.js
@@ -19,8 +19,14 @@ import * as rollup from 'rollup';
 
   const program_es5 = ts.createProgram(['src/entry-export_all.ts'], options_es5.options);
   const program_es8 = ts.createProgram(['src/entry-export_all.ts'], options_es8.options);
-  program_es5.emit();
-  program_es8.emit();
+  const result_es5 = program_es5.emit();
+  if (result_es5.emitSkipped) {
+    throw new Error(result_es5.diagnostics[0].messageText);
+  }
+  const result_es8 = program_es8.emit();
+  if (result_es8.emitSkipped) {
+    throw new Error(result_es8.diagnostics[0].messageText);
+  }
 
   // Copy non-ts resources
   await fs.copy('src/aes/aes.asm.js', 'dist_es5/aes/aes.asm.js');
diff --git a/tsconfig.json b/tsconfig.json
index 4b6424b..18e789e 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -4,6 +4,7 @@
     "target": "es2017",
     "lib": ["es5", "dom", "dom.iterable", "es6"],
     "noEmit": false,
+    "noEmitOnError": true,
     "strict": true,
     "sourceMap": false,
     "declaration": true,