Merge pull request #490 from hgrsd/fix-cache-false-positive

fix(cache): cache key comparison ignores milliseconds

src/cache.ts

@@ -4,6 +4,23 @@ import { isArray } from './helpers'
 
 export type CacheKeys = 'before' | 'after' | 'between'
 
+function argsMatch (
+  left: IterArgs[keyof IterArgs] | undefined,
+  right: IterArgs[keyof IterArgs] | undefined
+) {
+  if (Array.isArray(left)) {
+    if (!Array.isArray(right)) return false
+    if (left.length !== right.length) return false
+    return left.every((date, i) => date.getTime() === right[i].getTime())
+  }
+
+  if (left instanceof Date) {
+    return right instanceof Date && left.getTime() === right.getTime()
+  }
+
+  return left === right
+}
+
 export class Cache {
   all: Date[] | Partial<IterArgs> | false = false
   before: IterArgs[] = []
@@ -51,7 +68,7 @@ export class Cache {
     const findCacheDiff = function (item: IterArgs) {
       for (let i = 0; i < argsKeys.length; i++) {
         const key = argsKeys[i]
-        if (String(args![key]) !== String(item[key])) {
+        if (!argsMatch(args![key], item[key])) {
           return true
         }
       }
@@ -89,5 +106,4 @@ export class Cache {
         ? dateutil.clone(cached)
         : cached
   }
-
 }

test/cache.test.ts

@@ -0,0 +1,101 @@
+import { Cache } from "../src/cache";
+import { expect } from "chai";
+import { IterArgs } from "../src/iterresult";
+
+const dates = [
+  new Date("2021-01-01T00:00:00.000+00:00"),
+  new Date("2021-01-02T00:00:00.000+00:00"),
+  new Date("2021-01-03T00:00:00.000+00:00"),
+  new Date("2021-01-04T00:00:00.000+00:00"),
+  new Date("2021-01-05T00:00:00.000+00:00"),
+  new Date("2021-01-06T00:00:00.000+00:00"),
+  new Date("2021-01-07T00:00:00.000+00:00"),
+];
+
+describe("Cache", () => {
+  it("returns false for an empty cache", () => {
+    const cache = new Cache();
+    const args: Partial<IterArgs> = {
+      after: new Date("2021-01-01T00:00:00.000+00:00"),
+      before: new Date("2021-01-08T00:00:00.000+00:00"),
+      inc: true,
+    };
+
+    expect(cache._cacheGet("between", args)).to.be.false;
+  });
+
+  it("returns an empty array for a cached but empty set", () => {
+    const cache = new Cache();
+    const args: Partial<IterArgs> = {
+      after: new Date("2021-01-01T00:00:00.000+00:00"),
+      before: new Date("2021-01-08T00:00:00.000+00:00"),
+      inc: true,
+    };
+
+    cache._cacheAdd("between", [], args);
+
+    expect(cache._cacheGet("between", args)).to.eql([]);
+  });
+
+  it('returns cached entries if the "what" and the args both match', () => {
+    const cache = new Cache();
+    const args: Partial<IterArgs> = {
+      after: new Date("2021-01-01T00:00:00.000+00:00"),
+      before: new Date("2021-01-08T00:00:00.000+00:00"),
+      inc: true,
+    };
+
+    cache._cacheAdd("between", dates, args);
+
+    expect(cache._cacheGet("between", args)).to.eql(dates);
+  });
+
+  it('does not return cached entries if the "what" matches but the args do not', () => {
+    const cache = new Cache();
+    const args: Partial<IterArgs> = {
+      after: new Date("2021-01-01T00:00:00.000+00:00"),
+      before: new Date("2021-01-08T00:00:00.000+00:00"),
+      inc: true,
+    };
+
+    cache._cacheAdd("between", dates, args);
+
+    expect(
+      cache._cacheGet("between", {
+        ...args,
+        /** 1ms later than the args used for the insert */
+        after: new Date("2021-01-01T00:00:00.001+00:00"),
+      })
+    ).to.equal(false);
+  });
+
+  it('does not return cached entries if args match but the "what" does not', () => {
+    const cache = new Cache();
+    const args: Partial<IterArgs> = {
+      after: new Date("2021-01-01T00:00:00.000+00:00"),
+      before: new Date("2021-01-08T00:00:00.000+00:00"),
+      inc: true,
+    };
+
+    cache._cacheAdd("between", dates, args);
+
+    expect(cache._cacheGet("after", args)).to.equal(false);
+  });
+
+  it('reuses dates cached for the "all" method when querying using another method', () => {
+    const cache = new Cache();
+    const args: Partial<IterArgs> = {
+      after: new Date("2021-01-04T00:00:00.000+00:00"),
+      before: new Date("2021-01-06T00:00:00.000+00:00"),
+      inc: true,
+    };
+
+    cache._cacheAdd("all", dates);
+
+    expect(cache._cacheGet("between", args)).to.eql([
+      new Date("2021-01-04T00:00:00.000+00:00"),
+      new Date("2021-01-05T00:00:00.000+00:00"),
+      new Date("2021-01-06T00:00:00.000+00:00"),
+    ]);
+  });
+});