Initial release!

lib/util/Collection.js

@@ -0,0 +1,21 @@
+module.exports = class PikminCollection extends Map {
+  constructor() {
+    super();
+  }
+
+  filter(callback) {
+    let result = [];
+    for (const entry of Array.from(this.values())) {
+      if (callback(entry)) result.push(entry);
+    }
+
+    return result;
+  }
+
+  map(callback) {
+    let result = [];
+    for (const value of Array.from(this.values())) result.push(callback(value));
+
+    return result;
+  }
+};