feat: added full support for vertex mode

README.md

@@ -126,7 +126,7 @@ func ExampleLatLngToCell() {
 | `cellToVertex`               | TODO                                               |
 | `cellToVertexes`             | TODO                                               |
 | `vertexToLatLng`             | TODO                                               |
-| `isValidVertex`              | TODO                                               |
+| `isValidVertex`              | `IsValidVertex`                                    |
 | `gridDistance`               | `GridDistance`, `Cell#GridDistance`                |
 | `gridPathCells`              | `GridPath`, `Cell#GridPath`                        |
 | `cellToLocalIj`              | `CellToLocalIJ`                                    |

h3.go

@@ -713,6 +713,10 @@ func LocalIJToCell(origin Cell, ij CoordIJ) Cell {
 	return Cell(out)
 }
 
+func IsValidVertex(c Cell) bool {
+	return C.isValidVertex(C.H3Index(c)) == 1
+}
+
 func maxGridDiskSize(k int) int {
 	return 3*k*(k+1) + 1
 }

h3_test.go

@@ -609,6 +609,7 @@ func TestPentagons(t *testing.T) {
 	t.Parallel()
 
 	for _, res := range []int{0, 8, 15} {
+		res := res
 		t.Run(fmt.Sprintf("res=%d", res), func(t *testing.T) {
 			t.Parallel()
 			pentagons := Pentagons(res)
@@ -621,6 +622,13 @@ func TestPentagons(t *testing.T) {
 	}
 }
 
+func TestIsValidVertex(t *testing.T) {
+	t.Parallel()
+
+	assertFalse(t, IsValidVertex(0))
+	assertTrue(t, IsValidVertex(2473183460575936511))
+}
+
 func equalEps(expected, actual float64) bool {
 	return math.Abs(expected-actual) < eps
 }