handles integer with valida date format correctly

packages/gatsby/src/schema/__tests__/infer-graphql-type-test.js

@@ -118,6 +118,16 @@ describe(`GraphQL type inferance`, () => {
     expect(result.data.listNode[0].number).toEqual(1.1)
   })
 
+  it(`handles integer with valid date format`, async () => {
+    let result = await queryResult(
+      [{ number: 2018 }, { number: 1987 }],
+      `
+        number
+      `
+    )
+    expect(result.data.listNode[0].number).toEqual(2018)
+  })
+
   it(`handles date objects`, async () => {
     let result = await queryResult(
       [

packages/gatsby/src/schema/infer-graphql-type.js

@@ -107,7 +107,7 @@ function inferGraphQLType({
   // Check if this is a date.
   // All the allowed ISO 8601 date-time formats used.
   const momentDate = moment.utc(exampleValue, ISO_8601_FORMAT, true)
-  if (momentDate.isValid()) {
+  if (momentDate.isValid() && typeof exampleValue !== `number`) {
     return {
       type: GraphQLString,
       args: {