Merge pull request #3 from cajames/better-cache-keygen

src/__tests__/lib.spec.ts

@@ -187,6 +187,45 @@ describe("memorise", () => {
     expect(testFn).toHaveBeenCalledTimes(1);
   });
 
+  it("should treat undefined and null differently", () => {
+    const testFn = jest.fn();
+    const cachedFn = memorise(testFn);
+    cachedFn([undefined]);
+    cachedFn([null]);
+    expect(testFn).toHaveBeenCalledTimes(2);
+  });
+
+  it("should treat object with undefined values different to no keys at all", () => {
+    const testFn = jest.fn();
+    const cachedFn = memorise(testFn);
+    cachedFn({ a: undefined });
+    cachedFn({});
+    expect(testFn).toHaveBeenCalledTimes(2);
+  });
+
+  it("should support nested structures", () => {
+    const testFn = jest.fn();
+    const cachedFn = memorise(testFn);
+    cachedFn({ a: undefined });
+    cachedFn({});
+    expect(testFn).toHaveBeenCalledTimes(2);
+  });
+
+  it("should treat objects with same key,values equally, regardless of order", () => {
+    const testFn = jest.fn();
+    const cachedFn = memorise(testFn);
+    cachedFn({ a: 1, b: 2 });
+    cachedFn({ b: 2, a: 1 });
+    expect(testFn).toHaveBeenCalledTimes(1);
+  });
+
+  it("should treat single values and arrays differently", () => {
+    const testFn = jest.fn();
+    const cachedFn = memorise(testFn);
+    cachedFn(1);
+    cachedFn([1]);
+    expect(testFn).toHaveBeenCalledTimes(2);
+  });
   // Later features
   xit("should not cache a promise rejection when configured not to", async () => {});
   xit("should cache an error when configured to", async () => {});

src/lib.ts

@@ -105,5 +105,30 @@ const defaultGenCacheKey = (...args: any[]) => {
   if (args.length === 0) {
     return "no-args";
   }
-  return args.map((val) => JSON.stringify(val)).join("/");
+  return args
+    .map((val) => {
+      if (val === undefined) {
+        return "undefined";
+      }
+      if (val === null) {
+        return "null";
+      }
+      if (Array.isArray(val)) {
+        return `[${defaultGenCacheKey(...val)}]`;
+      }
+      if (typeof val === "object") {
+        return `{${defaultGenCacheKey(...sortedObjectEntries(val))}}`;
+      }
+      return JSON.stringify(val);
+    })
+    .join(",");
+};
+
+const sortedObjectEntries = (obj: any) => {
+  return Object.entries(obj).sort((a, b) => {
+    if (a[0] < b[0]) {
+      return -1;
+    }
+    return 1;
+  });
 };