@saeris/graphql-scalars/dist-src/dateTime.js

A collection of scalar types using Joi for validation

import { GraphQLScalarType, GraphQLError, Kind } from "graphql";
import { date as yupDate } from "yup";

const validate = value => yupDate().typeError(`Value is not a valid Date: ${value}`).validateSync(value);

export const DateTimeScalar = `scalar DateTime`;
export const DateTime = new GraphQLScalarType({
  name: `DateTime`,
  description: `Use JavaScript Date object for date/time fields.`,

  serialize(value) {
    const date = typeof value === `string` ? new Date(Date.parse(value)) : value;
    validate(date);
    return date.toJSON();
  },

  parseValue(value) {
    const date = new Date(value);
    return validate(date);
  },

  parseLiteral(ast) {
    if (ast.kind !== Kind.STRING) {
      throw new GraphQLError(`Can only parse strings to dates but got a: ${ast.kind}`);
    }

    const date = new Date(ast.value);

    if (ast.value !== date.toJSON()) {
      throw new GraphQLError(`Value is not a valid Date format (YYYY-MM-DDTHH:MM:SS.SSSZ): ${ast.value}`);
    }

    return validate(date);
  }

});