feat: make fragmentutils

Author: agviegas

packages/fragments/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@thatopen/fragments",
   "description": "Simple geometric system built on top of Three.js to display 3D BIM data efficiently.",
-  "version": "2.3.0-alpha.5",
+  "version": "2.3.0-alpha.6",
   "author": "That Open Company",
   "contributors": [
     "Antonio Gonzalez Viegas (https://github.com/agviegas)",

packages/fragments/src/fragment-utils.ts

@@ -0,0 +1,37 @@
+import { FragmentIdMap } from "./base-types";
+
+export class FragmentUtils {
+  static combine(maps: Iterable<FragmentIdMap>) {
+    const result: FragmentIdMap = {};
+    for (const map of maps) {
+      for (const fragID in map) {
+        if (!result[fragID]) {
+          result[fragID] = new Set<number>();
+        }
+        for (const expressID of map[fragID]) {
+          result[fragID].add(expressID);
+        }
+      }
+    }
+    return result;
+  }
+
+  static export(map: FragmentIdMap) {
+    const serialized: { [fragID: string]: number[] } = {};
+    for (const fragID in map) {
+      serialized[fragID] = Array.from(map[fragID]);
+    }
+    return JSON.stringify(serialized);
+  }
+
+  static import(serializedMap: string) {
+    const serialized = JSON.parse(serializedMap) as {
+      [fragID: string]: number[];
+    };
+    const map: FragmentIdMap = {};
+    for (const fragID in serialized) {
+      map[fragID] = new Set(serialized[fragID]);
+    }
+    return map;
+  }
+}

packages/fragments/src/index.ts

@@ -6,3 +6,4 @@ export * from "./fragment-mesh";
 export * from "./streamer-file-db";
 export * from "./civil";
 export * from "./stream-serializer";
+export * from "./fragment-utils";