Implement MergedMap pattern

debug/idv.ts

@@ -36,7 +36,7 @@ User: tirga
       const idv = Idv.parse(textarea.value);
 
       pre.textContent = JSON.stringify(
-        idv.getMap("User", UserFromDocument),
+        idv.getMergedMap("User", UserFromDocument),
         null,
         2
       );
@@ -49,8 +49,7 @@ User: tirga
   return [textarea, pre];
 }
 
-const UserFromDocument = (lines: string[]) => {
-  const idv = Idv.parseLines(lines);
+const UserFromDocument = (idv: Idv) => {
   return {
     shell: idv.getProperty("Shell", String, StringFromDocument),
     groups: idv.getList("Group", String, StringFromDocument),

lib/idv.ts

@@ -1,5 +1,6 @@
 export type DistinguisherParser<T> = (distinguisher: string) => T;
 export type DocumentParser<T> = (document: string[]) => T;
+export type IdvConverter<T> = (idv: Idv) => T;
 
 const LEADING_WHITESPACE = /^([ \t]+)/;
 const ENTRY = /^(.+?):\s*(.*)/;
@@ -104,6 +105,30 @@ export class Idv {
       ])
     );
   }
+
+  public getMergedMap<T>(
+    name: string,
+    convertIdv: IdvConverter<T>
+  ): Record<string, T> {
+    const idvMap: Map<string, Idv> = new Map();
+
+    (this.collections[name] ?? []).forEach(([distinguisher, document]) => {
+      let idv = idvMap.get(distinguisher);
+      if (idv == undefined) {
+        idvMap.set(distinguisher, (idv = new Idv()));
+      }
+
+      idv.importLines(document);
+    });
+
+    const result: Record<string, T> = {};
+
+    for (const [distinguisher, idv] of idvMap.entries()) {
+      result[distinguisher] = convertIdv(idv);
+    }
+
+    return result;
+  }
 }
 
 export const StringFromDocument = (lines: string[]) => lines.join("\n");