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

A collection of scalar types using Joi for validation

import { GraphQLScalarType, GraphQLError, Kind } from "graphql";
import { string as yupString } from "yup";
import postalCodes from "postal-codes-js";
const countries = [`US`, `GB`, `DE`, `CA`, `FR`, `IT`, `AU`, `NL`, `ES`, `DK`, `SE`, `BE`, `IN`];

const validate = value => yupString().strict(true).typeError(`Value is not string: ${value}`).test(`postal code`, `Value is not a valid postal code: ${value}`, val => countries.some(country => postalCodes.validate(country, val) === true)).validateSync(value);

export const PostalCodeScalar = `scalar PostalCode`;
export const PostalCode = new GraphQLScalarType({
  name: `PostalCode`,
  description: `A field whose value conforms to the standard postal code formats for United States, United Kingdom, Germany, Canada, France, Italy, Australia, Netherlands, Spain, Denmark, Sweden, Belgium or India.`,

  serialize(value) {
    return validate(value);
  },

  parseValue(value) {
    return validate(value);
  },

  parseLiteral(ast) {
    if (ast.kind !== Kind.STRING) {
      throw new GraphQLError(`Can only validate strings as phone numbers but got a: ${ast.kind}`);
    }

    return validate(ast.value);
  }

});