Prefer using HTTPS when merging IW maps

package.json

@@ -1,6 +1,6 @@
 {
     "name": "interlanguage-checker",
-    "version": "1.13.2",
+    "version": "1.13.3",
     "description": "Check the consistency of MediaWiki interlanguage links in a simple overview.",
     "author": "Felix W. Dekker",
     "browser": "dist/bundle.js",

src/main/js/MediaWiki.ts

@@ -598,7 +598,10 @@ export class MediaWikiManager {
      * @private
      */
     private updateIwMap(): void {
-        this.iwMap = mergeMaps([...this.mws.values()].map(mw => mw.interwikiMap));
+        this.iwMap = mergeMaps(
+            [...this.mws.values()].map(mw => mw.interwikiMap),
+            (k, v1, v2) => (v2.startsWith("https://")) ? v2 : v1
+        );
     }
 }
 

src/main/js/Shared.ts

@@ -5,16 +5,23 @@ export const couldNotConnectMessage: string =
     "Could not to connect to API. Is the URL correct? Are you using a script blocker? " +
     "See the <b>About</b> section for more information.";
 
-// TODO: Add a merge strategy (to prefer HTTPS)
 /**
  * Merges the given maps into a new map containing all their elements.
  *
  * @param maps the maps to merge into a single map
+ * @param merge a function to execute when both maps have the same key `k` with different values `v1` and `v2`; by
+ * default, the old value is used
  * @return the combined map
  */
-export const mergeMaps = <K, V>(maps: Map<K, V>[]): Map<K, V> => {
-    return maps.reduce((combined, map) => new Map([...combined, ...map]), new Map());
-}
+export const mergeMaps = <K, V>(maps: Map<K, V>[], merge: (k: K, v1: V, v2: V) => V = (k, v1, _) => v1): Map<K, V> => {
+    return maps.reduce((combined, map) => {
+        map.forEach((v, k) => {
+            if (combined.has(k)) combined.set(k, merge(k, combined.get(k), v));
+            combined.set(k, v);
+        });
+        return combined;
+    }, new Map());
+};
 
 /**
  * Merges the given sets into a new set containing all their elements.
@@ -24,4 +31,4 @@ export const mergeMaps = <K, V>(maps: Map<K, V>[]): Map<K, V> => {
  */
 export const mergeSets = <T>(sets: Set<T>[]): Set<T> => {
     return sets.reduce((combined, set) => new Set([...combined, ...set]), new Set());
-}
+};