Throw when parsing empty string to numeric scalar

Author: Robert Zhu

src/type/__tests__/serialization-test.js

@@ -81,6 +81,11 @@ describe('Type System: Scalar coercion', () => {
     expect(
       GraphQLInt.serialize(true)
     ).to.equal(1);
+    expect(() =>
+      GraphQLInt.serialize('')
+    ).to.throw(
+      'Int cannot represent non 32-bit signed integer value: (empty string)'
+    );
   });
 
   it('serializes output float', () => {
@@ -126,6 +131,12 @@ describe('Type System: Scalar coercion', () => {
     ).to.throw(
       'Float cannot represent non numeric value: one'
     );
+
+    expect(() =>
+      GraphQLFloat.serialize('')
+    ).to.throw(
+      'Float cannot represent non numeric value: (empty string)'
+    );
   });
 
   it('serializes output strings', () => {

src/type/scalars.js

@@ -20,6 +20,11 @@ const MAX_INT = 2147483647;
 const MIN_INT = -2147483648;
 
 function coerceInt(value: mixed): ?number {
+  if (value === '') {
+    throw new TypeError(
+      'Int cannot represent non 32-bit signed integer value: (empty string)'
+    );
+  }
   const num = Number(value);
   if (num === num && num <= MAX_INT && num >= MIN_INT) {
     return (num < 0 ? Math.ceil : Math.floor)(num);
@@ -48,6 +53,11 @@ export const GraphQLInt = new GraphQLScalarType({
 });
 
 function coerceFloat(value: mixed): ?number {
+  if (value === '') {
+    throw new TypeError(
+      'Float cannot represent non numeric value: (empty string)'
+    );
+  }
   const num = Number(value);
   if (num === num) {
     return num;