diff --git a/src/validate/js/index.js b/src/validate/js/index.js
index 60e34e111b32..bc3ab784f17c 100644
--- a/src/validate/js/index.js
+++ b/src/validate/js/index.js
@@ -16,43 +16,41 @@ export default function validateJs ( validator, js ) {
 		}
 
 		if ( node.type === 'ExportDefaultDeclaration' ) {
-			if ( validator.defaultExport ) {
-				validator.error( `Duplicate default export`, node.start );
+			if ( node.declaration.type !== 'ObjectExpression' ) {
+				return validator.error( `Default export must be an object literal`, node.declaration.start );
 			}
 
-			validator.defaultExport = node;
-		}
-	});
+			checkForComputedKeys( validator, node.declaration.properties );
+			checkForDupes( validator, node.declaration.properties );
+
+			node.declaration.properties.forEach( prop => {
+				validator.templateProperties[ prop.key.name ] = prop;
+			});
 
-	// ensure all exported props are valid
-	if ( validator.defaultExport ) {
-		checkForComputedKeys( validator, validator.defaultExport.declaration.properties );
-		checkForDupes( validator, validator.defaultExport.declaration.properties );
-
-		validator.defaultExport.declaration.properties.forEach( prop => {
-			validator.templateProperties[ prop.key.name ] = prop;
-		});
-
-		validator.defaultExport.declaration.properties.forEach( prop => {
-			const propValidator = propValidators[ prop.key.name ];
-
-			if ( propValidator ) {
-				propValidator( validator, prop );
-			} else {
-				const matches = fuzzySet.get( prop.key.name );
-				if ( matches && matches[0] && matches[0][0] > 0.7 ) {
-					validator.error( `Unexpected property '${prop.key.name}' (did you mean '${matches[0][1]}'?)`, prop.start );
-				} else if ( /FunctionExpression/.test( prop.value.type ) ) {
-					validator.error( `Unexpected property '${prop.key.name}' (did you mean to include it in 'methods'?)`, prop.start );
+			// ensure all exported props are valid
+			node.declaration.properties.forEach( prop => {
+				const propValidator = propValidators[ prop.key.name ];
+
+				if ( propValidator ) {
+					propValidator( validator, prop );
 				} else {
-					validator.error( `Unexpected property '${prop.key.name}'`, prop.start );
+					const matches = fuzzySet.get( prop.key.name );
+					if ( matches && matches[0] && matches[0][0] > 0.7 ) {
+						validator.error( `Unexpected property '${prop.key.name}' (did you mean '${matches[0][1]}'?)`, prop.start );
+					} else if ( /FunctionExpression/.test( prop.value.type ) ) {
+						validator.error( `Unexpected property '${prop.key.name}' (did you mean to include it in 'methods'?)`, prop.start );
+					} else {
+						validator.error( `Unexpected property '${prop.key.name}'`, prop.start );
+					}
 				}
+			});
+
+			if ( validator.templateProperties.namespace ) {
+				const ns = validator.templateProperties.namespace.value.value;
+				validator.namespace = namespaces[ ns ] || ns;
 			}
-		});
 
-		if ( validator.templateProperties.namespace ) {
-			const ns = validator.templateProperties.namespace.value.value;
-			validator.namespace = namespaces[ ns ] || ns;
+			validator.defaultExport = node;
 		}
-	}
+	});
 }
diff --git a/test/validate.js b/test/validate.js
index 597c9d7526a4..00f93c9c7227 100644
--- a/test/validate.js
+++ b/test/validate.js
@@ -46,9 +46,9 @@ describe( 'validate', () => {
 				if ( err.name !== 'ParseError' ) throw err;
 
 				try {
-					const expected = require( `./validator/${dir}/error.json` );
+					const expected = require( `./validator/${dir}/errors.json` )[0];
 
-					assert.equal( err.shortMessage, expected.message );
+					assert.equal( err.message, expected.message );
 					assert.deepEqual( err.loc, expected.loc );
 					assert.equal( err.pos, expected.pos );
 				} catch ( err2 ) {
diff --git a/test/validator/export-default-duplicated/errors.json b/test/validator/export-default-duplicated/errors.json
new file mode 100644
index 000000000000..3b8b22ff884d
--- /dev/null
+++ b/test/validator/export-default-duplicated/errors.json
@@ -0,0 +1,8 @@
+[{
+	"message": "Duplicate export 'default'",
+	"pos": 37,
+	"loc": {
+		"line": 3,
+		"column": 8
+	}
+}]
diff --git a/test/validator/export-default-duplicated/input.html b/test/validator/export-default-duplicated/input.html
new file mode 100644
index 000000000000..adceb3dce555
--- /dev/null
+++ b/test/validator/export-default-duplicated/input.html
@@ -0,0 +1,4 @@
+<script>
+	export default {};
+	export default {};
+</script>
diff --git a/test/validator/export-default-must-be-object/errors.json b/test/validator/export-default-must-be-object/errors.json
new file mode 100644
index 000000000000..e8106bdc126c
--- /dev/null
+++ b/test/validator/export-default-must-be-object/errors.json
@@ -0,0 +1,8 @@
+[{
+	"message": "Default export must be an object literal",
+	"pos": 25,
+	"loc": {
+		"line": 2,
+		"column": 16
+	}
+}]
diff --git a/test/validator/export-default-must-be-object/input.html b/test/validator/export-default-must-be-object/input.html
new file mode 100644
index 000000000000..0451644c7bf6
--- /dev/null
+++ b/test/validator/export-default-must-be-object/input.html
@@ -0,0 +1,3 @@
+<script>
+	export default potato;
+</script>