Fix Int coercion

Int is now properly coerced for values between 2^32 and MAX_INT. Fixes #69

Author: leebyron

src/type/__tests__/coercion.js

@@ -41,6 +41,14 @@ describe('Type System: Scalar coercion', () => {
     expect(
       GraphQLInt.coerce(1e5)
     ).to.equal(100000);
+    // Bigger than 2^32, but still representable as an Int
+    expect(
+      GraphQLInt.coerce(9876504321)
+    ).to.equal(9876504321);
+    expect(
+      GraphQLInt.coerce(-9876504321)
+    ).to.equal(-9876504321);
+    // Too big to represent as an Int
     expect(
       GraphQLInt.coerce(1e100)
     ).to.equal(null);

src/type/scalars.js

@@ -21,7 +21,10 @@ export var GraphQLInt = new GraphQLScalarType({
   name: 'Int',
   coerce(value) {
     var num = +value;
-    return num === num && num <= MAX_INT && num >= MIN_INT ? num | 0 : null;
+    if (num === num && num <= MAX_INT && num >= MIN_INT) {
+      return (num < 0 ? Math.ceil : Math.floor)(num);
+    }
+    return null;
   },
   coerceLiteral(ast) {
     if (ast.kind === Kind.INT) {
@@ -30,6 +33,7 @@ export var GraphQLInt = new GraphQLScalarType({
         return num;
       }
     }
+    return null;
   }
 });