implement some GEO commands, improve scan generic transformer, expose RPUSHX

lib/commands/GEOADD.ts

@@ -0,0 +1,49 @@
+import { GeoCoordinates, transformReplyNumber } from './generic-transformers';
+
+interface GeoMember extends GeoCoordinates {
+    member: string;
+}
+
+interface NX {
+    NX?: true;
+}
+
+interface XX {
+    XX?: true;
+}
+
+type SetGuards = NX | XX;
+
+interface GeoAddCommonOptions {
+    CH?: true;
+}
+
+type GeoAddOptions = SetGuards & GeoAddCommonOptions;
+
+export const FIRST_KEY_INDEX = 1;
+
+export function transformArguments(key: string, toAdd: GeoMember | Array<GeoMember>, options?: GeoAddOptions): Array<string> {
+    const args = ['GEOADD', key];
+
+    if ((options as NX)?.NX) {
+        args.push('NX');
+    } else if ((options as XX)?.XX) {
+        args.push('XX');
+    }
+
+    if (options?.CH) {
+        args.push('CH');
+    }
+
+    for (const { longitude, latitude, member } of (Array.isArray(toAdd) ? toAdd : [toAdd])) {
+        args.push(
+            longitude.toString(),
+            latitude.toString(),
+            member
+        );
+    }
+
+    return args;
+}
+
+export const transformReply = transformReplyNumber;