feat: create function to handle fetching data from multiple sources

This helps since sometimes the data sources have issues occasionally

src/libs/fetchFromMultipleSources.spec.ts

@@ -0,0 +1,92 @@
+import { describe, expect, it } from "bun:test";
+
+import { fetchFromMultipleSources } from "./fetchFromMultipleSources";
+
+describe("fetchFromMultipleSources", () => {
+  it("no promises, throws exception", () => {
+    expect(() => fetchFromMultipleSources([])).toThrow(
+      "fetchPromises cannot be empty",
+    );
+  });
+
+  it("has promises, returns first one with value", async () => {
+    const actual = await fetchFromMultipleSources<number>([
+      () => Promise.resolve(undefined),
+      () => Promise.resolve(null),
+      () => Promise.reject(),
+      () => Promise.resolve(2),
+      () => Promise.resolve(3),
+    ]);
+    const expected = 2;
+
+    expect(actual).toEqual(expected);
+  });
+
+  it("has promises, no valid responses, returns null", async () => {
+    const actual = await fetchFromMultipleSources<number>([
+      () => Promise.resolve(null),
+      () => Promise.reject(),
+      () => Promise.resolve(undefined),
+    ]);
+    const expected = null;
+
+    expect(actual).toBe(expected);
+  });
+
+  it("has promises, has cached value, returns cached value", async () => {
+    const actual = await fetchFromMultipleSources<number>(
+      [
+        () => Promise.resolve(null),
+        () => Promise.reject(),
+        () => Promise.resolve(undefined),
+      ],
+      {
+        fetchFromCache: () => Promise.resolve(-1),
+        saveInCache: async () => {},
+      },
+    );
+    const expected = -1;
+
+    expect(actual).toBe(expected);
+  });
+
+  it("has promises, no cached value, no valid response, should not save in cache", async () => {
+    let actual;
+    await fetchFromMultipleSources<number>(
+      [
+        () => Promise.resolve(null),
+        () => Promise.reject(),
+        () => Promise.resolve(undefined),
+      ],
+      {
+        fetchFromCache: () => Promise.resolve(null),
+        saveInCache: async (value) => {
+          actual = value;
+        },
+      },
+    );
+    const expected = undefined;
+
+    expect(actual).toBe(expected);
+  });
+
+  it("has promises, no cached value, has valid response, should save in cache", async () => {
+    let actual: number | undefined;
+    await fetchFromMultipleSources<number>(
+      [
+        () => Promise.resolve(null),
+        () => Promise.reject(),
+        () => Promise.resolve(3),
+      ],
+      {
+        fetchFromCache: () => Promise.resolve(null),
+        saveInCache: async (value) => {
+          actual = value;
+        },
+      },
+    );
+    const expected = 3;
+
+    expect(actual).toBe(expected);
+  });
+});