From 994a7b526675720f06dfa4bd4bca89a6ce82ce38 Mon Sep 17 00:00:00 2001
From: Thijs Louisse <Thijs.Louisse@ing.com>
Date: Fri, 17 May 2024 20:32:15 +0200
Subject: [PATCH] feat(providence): allow to clear cache of memoized function

---
 .../src/program/utils/memoize.js              | 43 ++++++++++---------
 .../test-node/program/utils/memoize.test.js   | 35 +++++++++++++--
 2 files changed, 55 insertions(+), 23 deletions(-)

diff --git a/packages-node/providence-analytics/src/program/utils/memoize.js b/packages-node/providence-analytics/src/program/utils/memoize.js
index 64c7927be..7dd730b11 100644
--- a/packages-node/providence-analytics/src/program/utils/memoize.js
+++ b/packages-node/providence-analytics/src/program/utils/memoize.js
@@ -24,30 +24,33 @@ function createCachableArg(arg) {
 
 /**
  * @template T
- * @type {<T extends Function>(functionToMemoize:T, opts?:{ storage?:object; }) => T}
+ * @type {<T extends Function>(functionToMemoize:T, opts?:{ cacheStorage?:object; }) => T & {clearCache:() => void}}
  */
-export function memoize(functionToMemoize, { storage = {} } = {}) {
-  return /** @type {* & T} */ (
-    function memoizedFn() {
-      // eslint-disable-next-line prefer-rest-params
-      const args = [...arguments];
-      const shouldSerialize = args.some(isObject);
+export function memoize(functionToMemoize, { cacheStorage = {} } = {}) {
+  function memoizedFn() {
+    // eslint-disable-next-line prefer-rest-params
+    const args = [...arguments];
+    const shouldSerialize = args.some(isObject);
 
-      const cachableArgs = shouldSerialize ? args.map(createCachableArg) : args;
-      // Allow disabling of cache for testing purposes
+    const cachableArgs = shouldSerialize ? args.map(createCachableArg) : args;
+    // Allow disabling of cache for testing purposes
+    // @ts-expect-error
+    if (shouldCache && cachableArgs in cacheStorage) {
       // @ts-expect-error
-      if (shouldCache && cachableArgs in storage) {
-        // @ts-expect-error
-        return storage[cachableArgs];
-      }
-      // @ts-expect-error
-      const outcome = functionToMemoize.apply(this, args);
-      // @ts-expect-error
-      // eslint-disable-next-line no-param-reassign
-      storage[cachableArgs] = outcome;
-      return outcome;
+      return cacheStorage[cachableArgs];
     }
-  );
+    // @ts-expect-error
+    const outcome = functionToMemoize.apply(this, args);
+    // @ts-expect-error
+    // eslint-disable-next-line no-param-reassign
+    cacheStorage[cachableArgs] = outcome;
+    return outcome;
+  }
+  memoizedFn.clearCache = () => {
+    // eslint-disable-next-line no-param-reassign
+    cacheStorage = {};
+  };
+  return /** @type {* & T & {clearCache:() => void}} */ (memoizedFn);
 }
 
 /**
diff --git a/packages-node/providence-analytics/test-node/program/utils/memoize.test.js b/packages-node/providence-analytics/test-node/program/utils/memoize.test.js
index 573726f3c..be40fb056 100644
--- a/packages-node/providence-analytics/test-node/program/utils/memoize.test.js
+++ b/packages-node/providence-analytics/test-node/program/utils/memoize.test.js
@@ -201,13 +201,13 @@ describe('Memoize', () => {
           sumCalled += 1;
           return { ...a, ...b };
         }
-        const sumMemoized = memoize(sum, { serializeObjects: true });
+        const sumMemoized = memoize(sum);
         let sum2Called = 0;
         function sum2(/** @type {object} a */ a, /** @type {object} a */ b) {
           sum2Called += 1;
           return { ...a, ...b };
         }
-        const sum2Memoized = memoize(sum2, { serializeObjects: true });
+        const sum2Memoized = memoize(sum2);
 
         expect(sumMemoized({ x: 1 }, { y: 2 })).to.deep.equal({ x: 1, y: 2 });
         expect(sumCalled).to.equal(1);
@@ -233,7 +233,7 @@ describe('Memoize', () => {
           sumCalled += 1;
           return { ...a, ...b };
         }
-        const sumMemoized = memoize(sum, { serializeObjects: true });
+        const sumMemoized = memoize(sum);
 
         // Put in cache for args combination
         const result = sumMemoized({ x: 1 }, { y: 2 });
@@ -313,4 +313,33 @@ describe('Memoize', () => {
       expect(sum2Called).to.equal(1);
     });
   });
+
+  describe('Cache', () => {
+    it(`"memoizedFn.clearCache()" clears the cache for a memoized fn"`, async () => {
+      let sumCalled = 0;
+      function sum(/** @type {string} a */ a, /** @type {string} a */ b) {
+        sumCalled += 1;
+        return a + b;
+      }
+      const sumMemoized = memoize(sum);
+
+      // Put in cache for args combination
+      expect(sumMemoized('1', '2')).to.equal('12');
+      expect(sumCalled).to.equal(1);
+
+      // Return from cache
+      expect(sumMemoized('1', '2')).to.equal('12');
+      expect(sumCalled).to.equal(1);
+
+      sumMemoized.clearCache();
+
+      // Now the original function is called again
+      expect(sumMemoized('1', '2')).to.equal('12');
+      expect(sumCalled).to.equal(3);
+
+      // Return from new cache again
+      expect(sumMemoized('1', '2')).to.equal('12');
+      expect(sumCalled).to.equal(3);
+    });
+  });
 });