fix: restore serialization of DateTime scalar to pre-1.2.0 (values must be serialized to string, not to instance of Date) + clarify that timestamps are ECMAScript (milliseconds), not unix timestamps (seconds)

src/scalars/iso-date/DateTime.ts

@@ -10,10 +10,15 @@
 import { GraphQLScalarType, Kind } from 'graphql';
 import type { GraphQLScalarTypeConfig } from 'graphql'; // eslint-disable-line
 import { validateJSDate, validateDateTime } from './validator.js';
-import { parseDateTime } from './formatter.js';
+import {
+  serializeDateTime,
+  serializeDateTimeString,
+  serializeTimestamp,
+  parseDateTime,
+} from './formatter.js';
 import { createGraphQLError } from '../../error.js';
 
-export const GraphQLDateTimeConfig: GraphQLScalarTypeConfig<Date, Date> = /*#__PURE__*/ {
+export const GraphQLDateTimeConfig: GraphQLScalarTypeConfig<Date, string> = /*#__PURE__*/ {
   name: 'DateTime',
   description:
     'A date-time string at UTC, such as 2007-12-03T10:15:30Z, ' +
@@ -23,19 +28,19 @@ export const GraphQLDateTimeConfig: GraphQLScalarTypeConfig<Date, Date> = /*#__P
   serialize(value) {
     if (value instanceof Date) {
       if (validateJSDate(value)) {
-        return value;
+        return serializeDateTime(value);
       }
       throw createGraphQLError('DateTime cannot represent an invalid Date instance');
     } else if (typeof value === 'string') {
       if (validateDateTime(value)) {
-        return parseDateTime(value);
+        return serializeDateTimeString(value);
       }
       throw createGraphQLError(`DateTime cannot represent an invalid date-time-string ${value}.`);
     } else if (typeof value === 'number') {
       try {
-        return new Date(value);
+        return serializeTimestamp(value);
       } catch (e) {
-        throw createGraphQLError('DateTime cannot represent an invalid Unix timestamp ' + value);
+        throw createGraphQLError('DateTime cannot represent an invalid timestamp ' + value);
       }
     } else {
       throw createGraphQLError(
@@ -88,7 +93,7 @@ export const GraphQLDateTimeConfig: GraphQLScalarTypeConfig<Date, Date> = /*#__P
  *
  * Output:
  *    This scalar serializes javascript Dates,
- *    RFC 3339 date-time strings and unix timestamps
+ *    RFC 3339 date-time strings and ECMAScript timestamps (number of milliseconds)
  *    to RFC 3339 UTC date-time strings.
  */
 export const GraphQLDateTime: GraphQLScalarType = /*#__PURE__*/ new GraphQLScalarType(GraphQLDateTimeConfig);

src/scalars/iso-date/formatter.ts

@@ -88,12 +88,18 @@ export const parseDateTime = (dateTime: string): Date => {
   return new Date(dateTime);
 };
 
+// Serializes a Date into an RFC 3339 compliant date-time-string
+// in the format YYYY-MM-DDThh:mm:ss.sssZ.
+export const serializeDateTime = (dateTime: Date): string => {
+  return dateTime.toISOString();
+};
+
 // Serializes an RFC 3339 compliant date-time-string by shifting
 // it to UTC.
-export const serializeDateTimeString = (dateTime: string): Date => {
+export const serializeDateTimeString = (dateTime: string): string => {
   // If already formatted to UTC then return the time string
   if (dateTime.indexOf('Z') !== -1) {
-    return new Date(dateTime);
+    return dateTime;
   } else {
     // These are time-strings with timezone information,
     // these need to be shifted to UTC.
@@ -112,15 +118,21 @@ export const serializeDateTimeString = (dateTime: string): Date => {
       // The date-time-string has no fractional part,
       // so we remove it from the dateTimeUTC variable.
       dateTimeUTC = dateTimeUTC.replace(regexFracSec, '');
-      return new Date(dateTimeUTC);
+      return dateTimeUTC;
     } else {
       // These are datetime-string with fractional seconds.
       // Make sure that we inject the fractional
       // second part back in. The `dateTimeUTC` variable
       // has millisecond precision, we may want more or less
       // depending on the string that was passed.
       dateTimeUTC = dateTimeUTC.replace(regexFracSec, fractionalPart[0]);
-      return new Date(dateTimeUTC);
+      return dateTimeUTC;
     }
   }
 };
+
+// Serializes ECMAScript timestamp (number of milliseconds) to an RFC 3339 compliant date-time-string
+// in the format YYYY-MM-DDThh:mm:ss.sssZ
+export const serializeTimestamp = (timestamp: number): string => {
+  return new Date(timestamp).toISOString();
+};

src/scalars/iso-date/validator.ts

@@ -140,17 +140,22 @@ export const validateDateTime = (dateTimeString: string): boolean => {
 };
 
 // Function that checks whether a given number is a valid
-// Unix timestamp.
+// ECMAScript timestamp.
 //
-// Unix timestamps are signed 32-bit integers. They are interpreted
-// as the number of seconds since 00:00:00 UTC on 1 January 1970.
+// ECMAScript are interpreted as the number of milliseconds
+// since 00:00:00 UTC on 1 January 1970.
 //
-export const validateUnixTimestamp = (timestamp: number): boolean => {
-  const MAX_INT = 2147483647;
-  const MIN_INT = -2147483648;
-  return (
-    timestamp === timestamp && timestamp <= MAX_INT && timestamp >= MIN_INT
-  ); // eslint-disable-line
+// It is defined in ECMA-262 that a maximum of ±100,000,000 days relative to
+// January 1, 1970 UTC (that is, April 20, 271821 BCE ~ September 13, 275760 CE)
+// can be represented by the standard Date object
+// (equivalent to ±8,640,000,000,000,000 milliseconds).
+//
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date#the_ecmascript_epoch_and_timestamps
+//
+export const validateTimestamp = (timestamp: number): boolean => {
+  const MAX = 8640000000000000;
+  const MIN = -8640000000000000;
+  return timestamp === timestamp && timestamp <= MAX && timestamp >= MIN; // eslint-disable-line
 };
 
 // Function that checks whether a javascript Date instance

tests/iso-date/DateTime.integration.test.ts

@@ -26,7 +26,7 @@ const schema = new GraphQLSchema({
         type: GraphQLDateTime,
         resolve: () => '2016-02-01T00:00:00-11:00',
       },
-      validUnixTimestamp: {
+      validTimestamp: {
         type: GraphQLDateTime,
         resolve: () => 854325678000,
       },
@@ -38,6 +38,10 @@ const schema = new GraphQLSchema({
         type: GraphQLDateTime,
         resolve: () => new Date('wrong'),
       },
+      invalidTimestamp: {
+        type: GraphQLDateTime,
+        resolve: () => Number.POSITIVE_INFINITY,
+      },
       invalidType: {
         type: GraphQLDateTime,
         resolve: () => [],
@@ -61,7 +65,7 @@ it('executes a query that includes a DateTime', async () => {
       validDate
       validUTCDateString
       validDateString
-      validUnixTimestamp
+      validTimestamp
       input(date: $date)
       inputNull: input
     }
@@ -73,11 +77,11 @@ it('executes a query that includes a DateTime', async () => {
 
   expect(response).toEqual({
     data: {
-      validDate: new Date('2016-05-02T10:31:42.200Z'),
-      validUTCDateString: new Date('1991-12-24T00:00:00Z'),
-      validDateString: new Date('2016-02-01T11:00:00Z'),
-      input: new Date('2017-10-01T00:00:00.000Z'),
-      validUnixTimestamp: new Date('1997-01-27T00:41:18.000Z'),
+      validDate: '2016-05-02T10:31:42.200Z',
+      validUTCDateString: '1991-12-24T00:00:00Z',
+      validDateString: '2016-02-01T11:00:00Z',
+      input: '2017-10-01T00:00:00.000Z',
+      validTimestamp: '1997-01-27T00:41:18.000Z',
       inputNull: null,
     },
   });
@@ -96,7 +100,7 @@ it('shifts an input date-time to UTC', async () => {
 
   expect(response).toEqual({
     data: {
-      input: new Date('2016-02-01T11:00:00.000Z'),
+      input: '2016-02-01T11:00:00.000Z',
     },
   });
 });
@@ -141,6 +145,7 @@ it('errors if an invalid date-time is returned from the resolver', async () => {
     {
       invalidDateString
       invalidDate
+      invalidTimestamp
       invalidType
     }
   `;
@@ -152,11 +157,13 @@ it('errors if an invalid date-time is returned from the resolver', async () => {
       "data": {
         "invalidDate": null,
         "invalidDateString": null,
+        "invalidTimestamp": null,
         "invalidType": null,
       },
       "errors": [
         [GraphQLError: DateTime cannot represent an invalid date-time-string 2017-01-001T00:00:00Z.],
         [GraphQLError: DateTime cannot represent an invalid Date instance],
+        [GraphQLError: DateTime cannot represent an invalid timestamp Infinity],
         [GraphQLError: DateTime cannot be serialized from a non string, non numeric or non Date type []],
       ],
     }

tests/iso-date/DateTime.test.ts

@@ -59,7 +59,7 @@ describe('GraphQLDateTime', () => {
       [new Date(Date.UTC(2016, 0, 1, 14, 48, 10, 30)), '2016-01-01T14:48:10.030Z'],
     ].forEach(([value, expected]) => {
       it(`serializes javascript Date ${stringify(value)} into ${stringify(expected)}`, () => {
-        expect(GraphQLDateTime.serialize(value).toJSON()).toEqual(expected);
+        expect(GraphQLDateTime.serialize(value)).toEqual(expected);
       });
     });
 
@@ -68,13 +68,17 @@ describe('GraphQLDateTime', () => {
     });
 
     [
+      ['2016-02-01T00:00:15Z', '2016-02-01T00:00:15Z'],
       ['2016-02-01T00:00:15.000Z', '2016-02-01T00:00:15.000Z'],
       ['2016-02-01T00:00:00.234Z', '2016-02-01T00:00:00.234Z'],
-      ['2016-02-01T00:00:00-11:00', '2016-02-01T11:00:00.000Z'],
-      ['2017-01-07T00:00:00.1+01:20', '2017-01-06T22:40:00.100Z'],
+      ['2016-02-01T00:00:00.23498Z', '2016-02-01T00:00:00.23498Z'],
+      ['2016-02-01T00:00:00-11:00', '2016-02-01T11:00:00Z'],
+      ['2016-02-01T00:00:00+11:00', '2016-01-31T13:00:00Z'],
+      ['2016-02-02T00:00:00.4567+01:30', '2016-02-01T22:30:00.4567Z'],
+      ['2017-01-07T00:00:00.1+01:20', '2017-01-06T22:40:00.1Z'],
     ].forEach(([input, output]) => {
       it(`serializes date-time-string ${input} into UTC date-time-string ${output}`, () => {
-        expect(GraphQLDateTime.serialize(input).toJSON()).toEqual(output);
+        expect(GraphQLDateTime.serialize(input)).toEqual(output);
       });
     });
 
@@ -84,21 +88,28 @@ describe('GraphQLDateTime', () => {
       });
     });
 
-    // Serializes Unix timestamp
+    // Serializes ECMAScript timestamp
     [
       [854325678000, '1997-01-27T00:41:18.000Z'],
+      [854325678123, '1997-01-27T00:41:18.123Z'],
       [876535000, '1970-01-11T03:28:55.000Z'],
-      // The maximum representable unix timestamp
-      [2147483647000, '2038-01-19T03:14:07.000Z'],
-      // The minimum representable unit timestamp
-      [-2147483648000, '1901-12-13T20:45:52.000Z'],
+      // The maximum representable ECMAScript timestamp
+      [8640000000000000, '+275760-09-13T00:00:00.000Z'],
+      // The minimum representable ECMAScript timestamp
+      [-8640000000000000, '-271821-04-20T00:00:00.000Z'],
     ].forEach(([value, expected]) => {
-      it(`serializes unix timestamp ${stringify(value)} into date-string ${expected}`, () => {
-        expect(GraphQLDateTime.serialize(value).toJSON()).toEqual(expected);
+      it(`serializes timestamp ${stringify(value)} into date-time-string ${expected}`, () => {
+        expect(GraphQLDateTime.serialize(value)).toEqual(expected);
       });
     });
   });
 
+  [Number.NaN, Number.POSITIVE_INFINITY, Number.POSITIVE_INFINITY].forEach(value => {
+    it(`throws an error serializing the invalid timestamp ${stringify(value)}`, () => {
+      expect(() => GraphQLDateTime.serialize(value)).toThrowErrorMatchingSnapshot();
+    });
+  });
+
   describe('value parsing', () => {
     validDates.forEach(([value, expected]) => {
       it(`parses date-string ${stringify(value)} into javascript Date ${stringify(expected)}`, () => {