Add isInteger coordinate utils

utils/coordinates.test.ts

@@ -4,7 +4,8 @@ import {
   findCoordsOfDigit,
   getAdjacent,
   inBounds,
-  isCoordinateEqual
+  isCoordinateEqual,
+  isInteger
 } from './coordinates.ts';
 
 describe('coordinates utils', () => {
@@ -101,4 +102,14 @@ describe('coordinates utils', () => {
     expect(actualSevenRegex[0]).toEqual([1, 2]);
     expect(actualSevenRegex[1]).toEqual([2, 3]);
   });
+
+  it('isInteger', () => {
+    expect(isInteger([1, 2])).toBeTrue();
+    expect(isInteger([1, 2, 3])).toBeTrue();
+    expect(isInteger([0, 0])).toBeTrue();
+    expect(isInteger([0, 10.001])).toBeFalse();
+    expect(isInteger([472.2948292, 10.001])).toBeFalse();
+    expect(isInteger([-472.2948292, 10.001])).toBeFalse();
+    expect(isInteger([-472.2948292, -10.001])).toBeFalse();
+  });
 });

utils/coordinates.ts

@@ -36,6 +36,14 @@ export function isCoordinateEqual(
   return b[0] === a[0] && b[1] === a[1];
 }
 
+/**
+ * Check if a xy-coordinate has integer coefficients.
+ * @param coordinate Coordinate
+ */
+export function isInteger(coordinate: Readonly<Coordinate | CoordinateSide>) {
+  return coordinate[0] % 1 === 0 && coordinate[1] % 1 === 0;
+}
+
 export type DirectNeighbours = 'top' | 'left' | 'right' | 'down';
 
 export type DiagonalNeighbours =