diff --git a/src/common/utils/__tests__/hash-set.test.ts b/src/common/utils/__tests__/hash-set.test.ts
new file mode 100644
index 0000000000..96e2f2502a
--- /dev/null
+++ b/src/common/utils/__tests__/hash-set.test.ts
@@ -0,0 +1,275 @@
+/**
+ * Copyright (c) 2021 OpenLens Authors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+import { ObservableHashSet } from "../hash-set";
+
+describe("ObservableHashSet<T>", () => {
+  it("should not throw on creation", () => {
+    expect(() => new ObservableHashSet<{ a: number }>([], item => item.a.toString())).not.toThrowError();
+  });
+
+  it("should be initializable", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    expect(res.size).toBe(4);
+  });
+
+  it("has should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    expect(res.has({ a: 1 })).toBe(true);
+    expect(res.has({ a: 5 })).toBe(false);
+  });
+
+  it("forEach should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    let a = 1;
+
+    res.forEach((item) => {
+      expect(item.a).toEqual(a++);
+    });
+  });
+
+  it("delete should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    expect(res.has({ a: 1 })).toBe(true);
+    expect(res.delete({ a: 1 })).toBe(true);
+    expect(res.has({ a: 1 })).toBe(false);
+    
+    expect(res.has({ a: 5 })).toBe(false);
+    expect(res.delete({ a: 5 })).toBe(false);
+    expect(res.has({ a: 5 })).toBe(false);
+  });
+
+  it("toggle should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    expect(res.has({ a: 1 })).toBe(true);
+    res.toggle({ a: 1 });
+    expect(res.has({ a: 1 })).toBe(false);
+
+    expect(res.has({ a: 6 })).toBe(false);
+    res.toggle({ a: 6 });
+    expect(res.has({ a: 6 })).toBe(true);
+  });
+
+  it("add should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    expect(res.has({ a: 6 })).toBe(false);
+    res.add({ a: 6 });
+    expect(res.has({ a: 6 })).toBe(true);
+  });
+
+  it("add should treat the hash to be the same as equality", () => {
+    const res = new ObservableHashSet([
+      { a: 1, foobar: "hello" },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    expect(res.has({ a: 1 })).toBe(true);
+    res.add({ a: 1, foobar: "goodbye" });
+    expect(res.has({ a: 1 })).toBe(true);
+  });
+
+  it("clear should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    expect(res.size).toBe(4);
+    res.clear();
+    expect(res.size).toBe(0);
+  });
+
+  it("replace should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    expect(res.size).toBe(4);
+    res.replace([{ a: 13 }]);
+    expect(res.size).toBe(1);
+    expect(res.has({ a: 1 })).toBe(false);
+    expect(res.has({ a: 13 })).toBe(true);
+  });
+
+  it("toJSON should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+
+    expect(res.toJSON()).toStrictEqual([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ]);
+  });
+
+  it("values should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+    const iter = res.values();
+
+    expect(iter.next()).toStrictEqual({ 
+      value: { a: 1 },
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: { a: 2 },
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: { a: 3 },
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: { a: 4 },
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: undefined,
+      done: true,
+    });
+  });
+
+  it("keys should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+    const iter = res.keys();
+
+    expect(iter.next()).toStrictEqual({ 
+      value: { a: 1 },
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: { a: 2 },
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: { a: 3 },
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: { a: 4 },
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: undefined,
+      done: true,
+    });
+  });
+
+  it("entries should work as expected", () => {
+    const res = new ObservableHashSet([
+      { a: 1 },
+      { a: 2 },
+      { a: 3 },
+      { a: 4 },
+    ], item => item.a.toString());
+    const iter = res.entries();
+
+    expect(iter.next()).toStrictEqual({ 
+      value: [{ a: 1 }, { a: 1 }],
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: [{ a: 2 }, { a: 2 }],
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: [{ a: 3 }, { a: 3 }],
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: [{ a: 4 }, { a: 4 }],
+      done: false,
+    });
+
+    expect(iter.next()).toStrictEqual({ 
+      value: undefined,
+      done: true,
+    });
+  });
+});
diff --git a/src/common/utils/__tests__/n-fircate.test.ts b/src/common/utils/__tests__/n-fircate.test.ts
new file mode 100644
index 0000000000..ad502d05e4
--- /dev/null
+++ b/src/common/utils/__tests__/n-fircate.test.ts
@@ -0,0 +1,55 @@
+/**
+ * Copyright (c) 2021 OpenLens Authors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+import { nFircate } from "../n-fircate";
+
+describe("nFircate", () => {
+  it("should produce an empty array if no parts are provided", () => {
+    expect(nFircate([{ a: 1 }, { a: 2 }], "a", []).length).toBe(0);
+  });
+
+  it("should ignore non-matching parts", () => {
+    const res = nFircate([{ a: 1 }, { a: 2 }], "a", [1]);
+    
+    expect(res.length).toBe(1);
+    expect(res[0].length).toBe(1);
+  });
+
+  it("should include all matching parts in each type", () => {
+    const res = nFircate([{ a: 1, b: "a" }, { a: 2, b: "b" }, { a: 1, b: "c" }], "a", [1, 2]);
+    
+    expect(res.length).toBe(2);
+    expect(res[0].length).toBe(2);
+    expect(res[0][0].b).toBe("a");
+    expect(res[0][1].b).toBe("c");
+    expect(res[1].length).toBe(1);
+    expect(res[1][0].b).toBe("b");
+  });
+
+  it("should throw a type error if the same part is provided more than once", () => {
+    try {
+      nFircate([{ a: 1, b: "a" }, { a: 2, b: "b" }, { a: 1, b: "c" }], "a", [1, 2, 1]);
+      fail("Expected error");
+    } catch (error) {
+      expect(error).toBeInstanceOf(TypeError);
+    }
+  });
+});
diff --git a/src/common/utils/hash-set.ts b/src/common/utils/hash-set.ts
index 358fc9e578..003f687ef6 100644
--- a/src/common/utils/hash-set.ts
+++ b/src/common/utils/hash-set.ts
@@ -21,7 +21,7 @@
 
 import { action, IInterceptable, IInterceptor, IListenable, ISetWillChange, observable, ObservableMap, ObservableSet } from "mobx";
 
-export function makeIterable<T>(iterator: Iterator<T>): IterableIterator<T> {
+export function makeIterableIterator<T>(iterator: Iterator<T>): IterableIterator<T> {
   (iterator as IterableIterator<T>)[Symbol.iterator] = () => iterator as IterableIterator<T>;
 
   return iterator as IterableIterator<T>;
@@ -30,7 +30,7 @@ export function makeIterable<T>(iterator: Iterator<T>): IterableIterator<T> {
 export class ObservableHashSet<T> implements Set<T>, IInterceptable<ISetWillChange>, IListenable {
   #hashmap: ObservableMap<string, T>;
 
-  get interceptors_(): IInterceptor<ISetWillChange<any>>[] {
+  get interceptors_(): IInterceptor<ISetWillChange<T>>[] {
     return [];
   }
 
@@ -68,7 +68,7 @@ export class ObservableHashSet<T> implements Set<T>, IInterceptable<ISetWillChan
   }
 
   @action
-  toggle(value: T) {
+  toggle(value: T): void {
     const hash = this.hasher(value);
 
     if (this.#hashmap.has(hash)) {
@@ -99,7 +99,7 @@ export class ObservableHashSet<T> implements Set<T>, IInterceptable<ISetWillChan
     const keys = Array.from(this.keys());
     const values = Array.from(this.values());
 
-    return makeIterable<[T, T]>({
+    return makeIterableIterator<[T, T]>({
       next() {
         const index = nextIndex++;
 
@@ -118,7 +118,7 @@ export class ObservableHashSet<T> implements Set<T>, IInterceptable<ISetWillChan
     let nextIndex = 0;
     const observableValues = Array.from(this.#hashmap.values());
 
-    return makeIterable<T>({
+    return makeIterableIterator<T>({
       next: () => {
         return nextIndex < observableValues.length
           ? { value: observableValues[nextIndex++], done: false }
diff --git a/src/common/utils/n-fircate.ts b/src/common/utils/n-fircate.ts
index 5a6350c710..289d391e3e 100644
--- a/src/common/utils/n-fircate.ts
+++ b/src/common/utils/n-fircate.ts
@@ -26,11 +26,16 @@
  * @param parts What each array will be filtered to
  * @returns A `parts.length` tuple of `T[]` where each array has matching `field` values
  */
+export function nFircate<T>(from: Iterable<T>, field: keyof T, parts: []): [];
 export function nFircate<T>(from: Iterable<T>, field: keyof T, parts: [T[typeof field]]): [T[]];
 export function nFircate<T>(from: Iterable<T>, field: keyof T, parts: [T[typeof field], T[typeof field]]): [T[], T[]];
 export function nFircate<T>(from: Iterable<T>, field: keyof T, parts: [T[typeof field], T[typeof field], T[typeof field]]): [T[], T[], T[]];
 
 export function nFircate<T>(from: Iterable<T>, field: keyof T, parts: T[typeof field][]): T[][] {
+  if (new Set(parts).size !== parts.length) {
+    throw new TypeError("Duplicate parts entries");
+  }
+
   const res = Array.from(parts, () => [] as T[]);
 
   for (const item of from) {