refactor: use number tuple as input for coordinate

src/address.ts

@@ -4,6 +4,75 @@ import type { Helpers } from './helpers';
 
 let f: Fake['fake'];
 
+/**
+ * Converts degrees to radians.
+ *
+ * @param degrees Degrees.
+ */
+function degreesToRadians(degrees: number): number {
+  return degrees * (Math.PI / 180.0);
+}
+
+/**
+ * Converts radians to degrees.
+ *
+ * @param radians Radians.
+ */
+function radiansToDegrees(radians: number): number {
+  return radians * (180.0 / Math.PI);
+}
+
+/**
+ * Converts kilometers to miles.
+ *
+ * @param miles Miles.
+ */
+function kilometersToMiles(miles: number): number {
+  return miles * 0.621371;
+}
+
+/**
+ * Calculates coordinates with offset.
+ *
+ * @param coordinate Coordinate.
+ * @param bearing Bearing.
+ * @param distance Distance.
+ * @param isMetric Metric: true, Miles: false.
+ */
+function coordinateWithOffset(
+  coordinate: [number, number],
+  bearing: number,
+  distance: number,
+  isMetric: boolean
+): number[] {
+  const R = 6378.137; // Radius of the Earth (http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html)
+  const d = isMetric ? distance : kilometersToMiles(distance); // Distance in km
+
+  const lat1 = degreesToRadians(coordinate[0]); //Current lat point converted to radians
+  const lon1 = degreesToRadians(coordinate[1]); //Current long point converted to radians
+
+  const lat2 = Math.asin(
+    Math.sin(lat1) * Math.cos(d / R) +
+      Math.cos(lat1) * Math.sin(d / R) * Math.cos(bearing)
+  );
+
+  let lon2 =
+    lon1 +
+    Math.atan2(
+      Math.sin(bearing) * Math.sin(d / R) * Math.cos(lat1),
+      Math.cos(d / R) - Math.sin(lat1) * Math.sin(lat2)
+    );
+
+  // Keep longitude in range [-180, 180]
+  if (lon2 > degreesToRadians(180)) {
+    lon2 = lon2 - degreesToRadians(360);
+  } else if (lon2 < degreesToRadians(-180)) {
+    lon2 = lon2 + degreesToRadians(360);
+  }
+
+  return [radiansToDegrees(lat2), radiansToDegrees(lon2)];
+}
+
 /**
  * Module to generate addresses and locations.
  */
@@ -448,63 +517,17 @@ export class Address {
    * faker.address.nearbyGPSCoordinate([33, -170]) // [ '33.0165', '-170.0636' ]
    * faker.address.nearbyGPSCoordinate([33, -170], 1000, true) // [ '37.9163', '-179.2408' ]
    */
-  // TODO ST-DDT 2022-02-10: This should use either string or number coords.
+  // TODO ST-DDT 2022-02-10: Allow coordinate parameter to be [string, string].
   nearbyGPSCoordinate(
-    coordinate?: number[],
+    coordinate?: [number, number],
     radius?: number,
     isMetric?: boolean
-  ): string[] {
-    // TODO ST-DDT 2022-02-10: Remove unused code.
-    function randomFloat(min: number, max: number): number {
-      return Math.random() * (max - min) + min;
-    }
-    function degreesToRadians(degrees: number): number {
-      return degrees * (Math.PI / 180.0);
-    }
-    function radiansToDegrees(radians: number): number {
-      return radians * (180.0 / Math.PI);
-    }
-    function kilometersToMiles(miles: number): number {
-      return miles * 0.621371;
-    }
-    function coordinateWithOffset(
-      coordinate: number[],
-      bearing: number,
-      distance: number,
-      isMetric: boolean
-    ): number[] {
-      const R = 6378.137; // Radius of the Earth (http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html)
-      const d = isMetric ? distance : kilometersToMiles(distance); // Distance in km
-
-      const lat1 = degreesToRadians(coordinate[0]); //Current lat point converted to radians
-      const lon1 = degreesToRadians(coordinate[1]); //Current long point converted to radians
-
-      const lat2 = Math.asin(
-        Math.sin(lat1) * Math.cos(d / R) +
-          Math.cos(lat1) * Math.sin(d / R) * Math.cos(bearing)
-      );
-
-      let lon2 =
-        lon1 +
-        Math.atan2(
-          Math.sin(bearing) * Math.sin(d / R) * Math.cos(lat1),
-          Math.cos(d / R) - Math.sin(lat1) * Math.sin(lat2)
-        );
-
-      // Keep longitude in range [-180, 180]
-      if (lon2 > degreesToRadians(180)) {
-        lon2 = lon2 - degreesToRadians(360);
-      } else if (lon2 < degreesToRadians(-180)) {
-        lon2 = lon2 + degreesToRadians(360);
-      }
-
-      return [radiansToDegrees(lat2), radiansToDegrees(lon2)];
-    }
-
+  ): [string, string] {
     // If there is no coordinate, the best we can do is return a random GPS coordinate.
     if (coordinate === undefined) {
       return [this.faker.address.latitude(), this.faker.address.longitude()];
     }
+
     radius = radius || 10.0;
     isMetric = isMetric || false;