[PM-7289] implement generator libraries (#9549)

This is a copy of the files. The source in `@bitwarden/common` will be deleted once
all of the applications have been ported to the library.

libs/common/src/tools/rx.spec.ts

@@ -0,0 +1,86 @@
+/**
+ * include structuredClone in test environment.
+ * @jest-environment ../../../../shared/test.environment.ts
+ */
+import { of, firstValueFrom } from "rxjs";
+
+import { awaitAsync, trackEmissions } from "../../spec";
+
+import { distinctIfShallowMatch, reduceCollection } from "./rx";
+
+describe("reduceCollection", () => {
+  it.each([[null], [undefined], [[]]])(
+    "should return the default value when the collection is %p",
+    async (value: number[]) => {
+      const reduce = (acc: number, value: number) => acc + value;
+      const source$ = of(value);
+
+      const result$ = source$.pipe(reduceCollection(reduce, 100));
+      const result = await firstValueFrom(result$);
+
+      expect(result).toEqual(100);
+    },
+  );
+
+  it("should reduce the collection to a single value", async () => {
+    const reduce = (acc: number, value: number) => acc + value;
+    const source$ = of([1, 2, 3]);
+
+    const result$ = source$.pipe(reduceCollection(reduce, 0));
+    const result = await firstValueFrom(result$);
+
+    expect(result).toEqual(6);
+  });
+});
+
+describe("distinctIfShallowMatch", () => {
+  it("emits a single value", async () => {
+    const source$ = of({ foo: true });
+    const pipe$ = source$.pipe(distinctIfShallowMatch());
+
+    const result = trackEmissions(pipe$);
+    await awaitAsync();
+
+    expect(result).toEqual([{ foo: true }]);
+  });
+
+  it("emits different values", async () => {
+    const source$ = of({ foo: true }, { foo: false });
+    const pipe$ = source$.pipe(distinctIfShallowMatch());
+
+    const result = trackEmissions(pipe$);
+    await awaitAsync();
+
+    expect(result).toEqual([{ foo: true }, { foo: false }]);
+  });
+
+  it("emits new keys", async () => {
+    const source$ = of({ foo: true }, { foo: true, bar: true });
+    const pipe$ = source$.pipe(distinctIfShallowMatch());
+
+    const result = trackEmissions(pipe$);
+    await awaitAsync();
+
+    expect(result).toEqual([{ foo: true }, { foo: true, bar: true }]);
+  });
+
+  it("suppresses identical values", async () => {
+    const source$ = of({ foo: true }, { foo: true });
+    const pipe$ = source$.pipe(distinctIfShallowMatch());
+
+    const result = trackEmissions(pipe$);
+    await awaitAsync();
+
+    expect(result).toEqual([{ foo: true }]);
+  });
+
+  it("suppresses removed keys", async () => {
+    const source$ = of({ foo: true, bar: true }, { foo: true });
+    const pipe$ = source$.pipe(distinctIfShallowMatch());
+
+    const result = trackEmissions(pipe$);
+    await awaitAsync();
+
+    expect(result).toEqual([{ foo: true, bar: true }]);
+  });
+});