Latitude & Longitude scalars (#748)

* Added Latitude & Longitude scalars

* Added Latitude & Longitude scalars fix

README.md

@@ -98,6 +98,10 @@ scalar ISBN
 
 scalar JWT
 
+scalar Latitude
+
+scalar Longitude
+
 scalar MAC
 
 scalar Port
@@ -158,6 +162,8 @@ import {
   IPv6Resolver,
   ISBNResolver,
   JWTResolver,
+  LatitudeResolver,
+  LongitudeResolver,
   MACResolver,
   PortResolver,
   RGBResolver,
@@ -225,6 +231,9 @@ const myResolverMap = {
 
   JWT: JWTResolver,
 
+  Latitude: LatitudeResolver,
+  Longitude: LongitudeResolver,
+
   USCurrency: USCurrencyResolver,
   Currency: CurrencyResolver,
   JSON: JSONResolver,
@@ -714,9 +723,34 @@ A field whose value is a [IPv6 address](https://en.wikipedia.org/wiki/IPv6).
 A field whose value is a [ISBN-10 or ISBN-13 number](https://en.wikipedia.org/wiki/International_Standard_Book_Number).
 
 ### JWT
+
 A field whose value is a [JSON Web Token (JWT)](https://jwt.io/introduction).
 
-The scalar checks only the format (*header.payload.signature*) using a regex and not the validity (signature) of the token.
+The scalar checks only the format (_header.payload.signature_) using a regex and not the validity (signature) of the token.
+
+### Latitude
+
+A field whose value is a valid [decimal degrees latitude number](https://en.wikipedia.org/wiki/Latitude) (53.471).
+
+The **input** value can be either in _decimal_ (53.471) or _sexagesimal_ (53° 21' 16") format.
+
+The **output** value is always in _decimal_ format (53.471).
+
+The maximum decimal degrees **precision** is **8**. See [Decimal Degrees Precision](https://en.wikipedia.org/wiki/Decimal_degrees#Precision) for more information.
+
+_This scalar is inspired by [Geolib](https://github.com/manuelbieh/geolib)._
+
+### Longitude
+
+A field whose value is a valid [decimal degrees longitude number](https://en.wikipedia.org/wiki/Longitude) (53.471).
+
+The **input** value can be either in _decimal_ (53.471) or _sexagesimal_ (53° 21' 16") format.
+
+The **output** value is always in _decimal_ format (53.471).
+
+The maximum decimal degrees **precision** is **8**. See [Decimal Degrees Precision](https://en.wikipedia.org/wiki/Decimal_degrees#Precision) for more information.
+
+_This scalar is inspired by [Geolib](https://github.com/manuelbieh/geolib)._
 
 ### MAC
 

src/index.ts

@@ -39,6 +39,8 @@ import {
   GraphQLIPv6,
   GraphQLISBN,
   GraphQLJWT,
+  GraphQLLatitude,
+  GraphQLLongitude,
   GraphQLMAC,
   GraphQLPort,
   GraphQLRGB,
@@ -91,6 +93,8 @@ export {
   IPv6 as IPv6Definition,
   ISBN as ISBNDefinition,
   JWT as JWTDefinition,
+  Latitude as LatitudeDefinition,
+  Longitude as LongitudeDefinition,
   MAC as MACDefinition,
   Port as PortDefinition,
   RGB as RGBDefinition,
@@ -146,6 +150,8 @@ export {
   GraphQLIPv6 as IPv6Resolver,
   GraphQLISBN as ISBNResolver,
   GraphQLJWT as JWTResolver,
+  GraphQLLatitude as LatitudeResolver,
+  GraphQLLongitude as LongitudeResolver,
   GraphQLMAC as MACResolver,
   GraphQLPort as PortResolver,
   GraphQLRGB as RGBResolver,
@@ -199,6 +205,8 @@ export const resolvers = {
   IPv6: GraphQLIPv6,
   ISBN: GraphQLISBN,
   JWT: GraphQLJWT,
+  Latitude: GraphQLLatitude,
+  Longitude: GraphQLLongitude,
   MAC: GraphQLMAC,
   Port: GraphQLPort,
   RGB: GraphQLRGB,
@@ -252,6 +260,8 @@ export {
   IPv6 as IPv6Mock,
   ISBN as ISBNMock,
   JWT as JWTMock,
+  Latitude as LatitudeMock,
+  Longitude as LongitudeMock,
   MAC as MACMock,
   Port as PortMock,
   RGB as RGBMock,
@@ -309,6 +319,8 @@ export {
   GraphQLIPv6,
   GraphQLISBN,
   GraphQLJWT,
+  GraphQLLatitude,
+  GraphQLLongitude,
   GraphQLMAC,
   GraphQLPort,
   GraphQLRGB,

src/mocks.ts

@@ -104,6 +104,8 @@ export const JWT = () => {
   // }
   return `eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwiaWF0IjoxNTE2MjM5MDIyLCJwcm9qZWN0IjoiZ3JhcGhxbC1zY2FsYXJzIn0.nYdrSfE2nNRAgpiEU1uKgn2AYYKLo28Z0nhPXvsuIww`;
 };
+export const Latitude = () => 41.902782;
+export const Longitude = () => 12.496366;
 export const USCurrency = () => 1000;
 export const Currency = () => 'USD';
 export const JSON = () => ({});

src/scalars/Latitude.ts

@@ -0,0 +1,65 @@
+// Inspired by Geolib: https://github.com/manuelbieh/geolib
+import { GraphQLError, GraphQLScalarType, Kind } from 'graphql';
+import { isDecimal, isSexagesimal, sexagesimalToDecimal } from './utilities';
+
+// Minimum latitude
+const MIN_LAT = -90.0;
+// Maximum latitude
+const MAX_LAT = 90.0;
+// See https://en.wikipedia.org/wiki/Decimal_degrees#Precision
+const MAX_PRECISION = 8;
+
+const validate = (value: any): number => {
+  // Check if value is a string or a number
+  if (
+    (typeof value !== 'string' && typeof value !== 'number') ||
+    value === null ||
+    typeof value === 'undefined' ||
+    Number.isNaN(value)
+  ) {
+    throw new TypeError(`Value is neither a number nor a string: ${value}`);
+  }
+
+  if (isDecimal(value)) {
+    const decimalValue =
+      typeof value === 'string' ? Number.parseFloat(value) : value;
+
+    if (decimalValue < MIN_LAT || decimalValue > MAX_LAT) {
+      throw new RangeError(
+        `Value must be between ${MIN_LAT} and ${MAX_LAT}: ${value}`,
+      );
+    }
+
+    return Number.parseFloat(decimalValue.toFixed(MAX_PRECISION));
+  }
+
+  if (isSexagesimal(value)) {
+    return validate(sexagesimalToDecimal(value));
+  }
+
+  throw new TypeError(`Value is not a valid latitude: ${value}`);
+};
+
+export const GraphQLLatitude = /*#__PURE__*/ new GraphQLScalarType({
+  name: `Latitude`,
+
+  description: `A field whose value is a valid decimal degrees latitude number (53.471): https://en.wikipedia.org/wiki/Latitude`,
+
+  serialize(value) {
+    return validate(value);
+  },
+
+  parseValue(value) {
+    return validate(value);
+  },
+
+  parseLiteral(ast) {
+    if (ast.kind !== Kind.FLOAT && ast.kind !== Kind.STRING) {
+      throw new GraphQLError(
+        `Can only validate floats or strings as latitude but got a: ${ast.kind}`,
+      );
+    }
+
+    return validate(ast.value);
+  },
+});

src/scalars/Longitude.ts

@@ -0,0 +1,65 @@
+// Inspired by Geolib: https://github.com/manuelbieh/geolib
+import { GraphQLError, GraphQLScalarType, Kind } from 'graphql';
+import { isDecimal, isSexagesimal, sexagesimalToDecimal } from './utilities';
+
+// Minimum longitude
+const MIN_LON = -180.0;
+// Maximum longitude
+const MAX_LON = 180.0;
+// See https://en.wikipedia.org/wiki/Decimal_degrees#Precision
+const MAX_PRECISION = 8;
+
+const validate = (value: any): number => {
+  // Check if value is a string or a number
+  if (
+    (typeof value !== 'string' && typeof value !== 'number') ||
+    value === null ||
+    typeof value === 'undefined' ||
+    Number.isNaN(value)
+  ) {
+    throw new TypeError(`Value is neither a number nor a string: ${value}`);
+  }
+
+  if (isDecimal(value)) {
+    const decimalValue =
+      typeof value === 'string' ? Number.parseFloat(value) : value;
+
+    if (decimalValue < MIN_LON || decimalValue > MAX_LON) {
+      throw new RangeError(
+        `Value must be between ${MIN_LON} and ${MAX_LON}: ${value}`,
+      );
+    }
+
+    return Number.parseFloat(decimalValue.toFixed(MAX_PRECISION));
+  }
+
+  if (isSexagesimal(value)) {
+    return validate(sexagesimalToDecimal(value));
+  }
+
+  throw new TypeError(`Value is not a valid longitude: ${value}`);
+};
+
+export const GraphQLLongitude = /*#__PURE__*/ new GraphQLScalarType({
+  name: `Longitude`,
+
+  description: `A field whose value is a valid decimal degrees longitude number (53.471): https://en.wikipedia.org/wiki/Longitude`,
+
+  serialize(value) {
+    return validate(value);
+  },
+
+  parseValue(value) {
+    return validate(value);
+  },
+
+  parseLiteral(ast) {
+    if (ast.kind !== Kind.FLOAT && ast.kind !== Kind.STRING) {
+      throw new GraphQLError(
+        `Can only validate floats or strings as longitude but got a: ${ast.kind}`,
+      );
+    }
+
+    return validate(ast.value);
+  },
+});

src/scalars/index.ts

@@ -36,6 +36,8 @@ export { GraphQLIPv4 } from './IPv4';
 export { GraphQLIPv6 } from './IPv6';
 export { GraphQLISBN } from './ISBN';
 export { GraphQLJWT } from './JWT';
+export { GraphQLLatitude } from './Latitude';
+export { GraphQLLongitude } from './Longitude';
 export { GraphQLMAC } from './MAC';
 export { GraphQLPort } from './Port';
 export { GraphQLRGB } from './RGB';

src/scalars/utilities.ts

@@ -10,6 +10,9 @@ enum VALUE_TYPES {
   FLOAT,
 }
 
+// More info about Sexagesimal: https://en.wikipedia.org/wiki/Sexagesimal
+const SEXAGESIMAL_REGEX = /^([0-9]{1,3})°\s*([0-9]{1,3}(?:\.(?:[0-9]{1,}))?)['′]\s*(([0-9]{1,3}(\.([0-9]{1,}))?)["″]\s*)?([NEOSW]?)$/;
+
 // TODO: Consider implementing coercion like this...
 // See: https://github.com/graphql/graphql-js/blob/master/src/type/scalars.js#L13
 // See: https://github.com/graphql/graphql-js/blob/master/src/type/scalars.js#L60
@@ -117,3 +120,53 @@ export function processValue(value: any, scalarName: string) {
 
   return parsedValue;
 }
+
+/**
+ * Check if the value is in decimal format.
+ *
+ * @param value - Value to check
+ * @returns True if is decimal, false otherwise
+ */
+export function isDecimal(value: any): boolean {
+  const checkedValue = value.toString().trim();
+
+  if (Number.isNaN(Number.parseFloat(checkedValue))) {
+    return false;
+  }
+
+  return Number.parseFloat(checkedValue) === Number(checkedValue);
+}
+
+/**
+ * Check if the value is in sexagesimal format.
+ *
+ * @param value - Value to check
+ * @returns True if sexagesimal, false otherwise
+ */
+export function isSexagesimal(value: any): boolean {
+  if (typeof value !== 'string') return false;
+
+  return SEXAGESIMAL_REGEX.test(value.toString().trim());
+}
+
+/**
+ * Converts a sexagesimal coordinate to decimal format.
+ *
+ * @param value - Value to convert
+ * @returns Decimal coordinate
+ * @throws {TypeError} if the value is not in sexagesimal format
+ */
+export function sexagesimalToDecimal(value: any) {
+  const data = SEXAGESIMAL_REGEX.exec(value);
+
+  if (typeof data === 'undefined' || data === null) {
+    throw new TypeError(`Value is not in sexagesimal format: ${value}`);
+  }
+
+  const min = Number(data[2]) / 60 || 0;
+  const sec = Number(data[4]) / 3600 || 0;
+  const decimal = Number.parseFloat(data[1]) + min + sec;
+
+  // Southern and western coordinates must be negative decimals
+  return ['S', 'W'].includes(data[7]) ? -decimal : decimal;
+}

src/typeDefs.ts

@@ -21,6 +21,8 @@ export const IPv4 = `scalar IPv4`;
 export const IPv6 = `scalar IPv6`;
 export const ISBN = `scalar ISBN`;
 export const JWT = `scalar JWT`;
+export const Latitude = `scalar Latitude`;
+export const Longitude = `scalar Longitude`;
 export const JSON = `scalar JSON`;
 export const JSONObject = `scalar JSONObject`;
 export const MAC = `scalar MAC`;
@@ -90,6 +92,8 @@ export const typeDefs = [
   IPv6,
   ISBN,
   JWT,
+  Latitude,
+  Longitude,
   MAC,
   Port,
   RGB,