add comments to decode_geo_hash lost by refactor to typescript (#43789) (#43818)

src/legacy/ui/public/utils/__tests__/decode_geo_hash.test.js

@@ -17,14 +17,27 @@
  * under the License.
  */
 
-import expect from '@kbn/expect';
-import { geohashColumns } from '../decode_geo_hash';
+import { geohashColumns, decodeGeoHash } from '../decode_geo_hash';
 
-describe('decode_geo_hash', function () {
-  it('geohashColumns', function () {
-    expect(geohashColumns(1)).to.equal(8);
-    expect(geohashColumns(2)).to.equal(8 * 4);
-    expect(geohashColumns(3)).to.equal(8 * 4 * 8);
-    expect(geohashColumns(4)).to.equal(8 * 4 * 8 * 4);
+test('geohashColumns', function () {
+  expect(geohashColumns(1)).toBe(8);
+  expect(geohashColumns(2)).toBe(8 * 4);
+  expect(geohashColumns(3)).toBe(8 * 4 * 8);
+  expect(geohashColumns(4)).toBe(8 * 4 * 8 * 4);
+});
+
+test('decodeGeoHash', function () {
+  expect(decodeGeoHash('drm3btev3e86')).toEqual({
+    latitude: [
+      41.119999922811985,
+      41.12000009045005,
+      41.12000000663102,
+    ],
+    longitude: [
+      -71.34000029414892,
+      -71.3399999588728,
+      -71.34000012651086,
+    ],
   });
 });
+

src/legacy/ui/public/utils/decode_geo_hash.ts

@@ -17,12 +17,17 @@
  * under the License.
  */
 
-interface Coordinates {
+interface DecodedGeoHash {
   latitude: number[];
   longitude: number[];
 }
 
-export function decodeGeoHash(geohash: number[]): Coordinates {
+/**
+ * Decodes geohash to object containing
+ * top-left and bottom-right corners of
+ * rectangle and center point.
+ */
+export function decodeGeoHash(geohash: string): DecodedGeoHash {
   const BITS: number[] = [16, 8, 4, 2, 1];
   const BASE32: string = '0123456789bcdefghjkmnpqrstuvwxyz';
   let isEven: boolean = true;
@@ -34,9 +39,8 @@ export function decodeGeoHash(geohash: number[]): Coordinates {
   lon[1] = 180.0;
   let latErr: number = 90.0;
   let lonErr: number = 180.0;
-  for (const geohashEl of geohash) {
-    const c: string = geohashEl.toString();
-    const cd: number = BASE32.indexOf(c);
+  [...geohash].forEach((nextChar: string) => {
+    const cd: number = BASE32.indexOf(nextChar);
     for (let j = 0; j < 5; j++) {
       const mask: number = BITS[j];
       if (isEven) {
@@ -48,13 +52,13 @@ export function decodeGeoHash(geohash: number[]): Coordinates {
       }
       isEven = !isEven;
     }
-  }
+  });
   lat[2] = (lat[0] + lat[1]) / 2;
   lon[2] = (lon[0] + lon[1]) / 2;
   return {
     latitude: lat,
     longitude: lon,
-  } as Coordinates;
+  } as DecodedGeoHash;
 }
 
 function refineInterval(interval: number[], cd: number, mask: number) {