feat(providence-analytics): enhance and test memoization

.changeset/pink-games-grin.md

@@ -0,0 +1,5 @@
+---
+'providence-analytics': patch
+---
+
+improve memoization

packages-node/providence-analytics/src/program/analyzers/helpers/track-down-identifier.js

@@ -7,7 +7,7 @@ const {
 const { resolveImportPath } = require('../../utils/resolve-import-path.js');
 const { AstService } = require('../../services/AstService.js');
 const { LogService } = require('../../services/LogService.js');
-const { memoizeAsync } = require('../../utils/memoize.js');
+const { memoize } = require('../../utils/memoize.js');
 
 /**
  * @typedef {import('../../types/core').RootFile} RootFile
@@ -233,7 +233,7 @@ async function trackDownIdentifierFn(source, identifierName, currentFilePath, ro
   return /** @type { RootFile } */ { file: rootFilePath, specifier: rootSpecifier };
 }
 
-trackDownIdentifier = memoizeAsync(trackDownIdentifierFn);
+trackDownIdentifier = memoize(trackDownIdentifierFn);
 
 /**
  * @param {BabelPath} astPath
@@ -265,7 +265,7 @@ async function trackDownIdentifierFromScopeFn(
   return rootFile;
 }
 
-const trackDownIdentifierFromScope = memoizeAsync(trackDownIdentifierFromScopeFn);
+const trackDownIdentifierFromScope = memoize(trackDownIdentifierFromScopeFn);
 
 module.exports = {
   trackDownIdentifier,

packages-node/providence-analytics/src/program/utils/memoize.js

@@ -1,54 +1,45 @@
 const { InputDataService } = require('../services/InputDataService.js');
 
+function isObject(arg) {
+  return !Array.isArray(arg) && typeof arg === 'object';
+}
+
+function createCachableArg(arg) {
+  if (isObject(arg)) {
+    try {
+      return JSON.stringify(arg);
+    } catch {
+      return arg;
+    }
+  }
+  return arg;
+}
+
 /**
- * @param {function} func
- * @param {object} [storage]
+ * @param {function} functionToMemoize
+ * @param {{ storage:object; serializeObjects: boolean }} [opts]
  */
-function memoize(func, storage = {}) {
+function memoize(functionToMemoize, { storage = {}, serializeObjects = false } = {}) {
   // eslint-disable-next-line func-names
   return function () {
     // eslint-disable-next-line prefer-rest-params
     const args = [...arguments];
+    const cachableArgs = !serializeObjects ? args : args.map(createCachableArg);
     // Allow disabling of cache for testing purposes
     // @ts-ignore
-    if (!InputDataService.cacheDisabled && args in storage) {
+    if (!InputDataService.cacheDisabled && cachableArgs in storage) {
       // @ts-ignore
-      return storage[args];
+      return storage[cachableArgs];
     }
     // @ts-ignore
-    const outcome = func.apply(this, args);
+    const outcome = functionToMemoize.apply(this, args);
     // @ts-ignore
     // eslint-disable-next-line no-param-reassign
-    storage[args] = outcome;
-    return outcome;
-  };
-}
-
-/**
- * @param {function} func
- * @param {object} [storage]
- */
-function memoizeAsync(func, storage = {}) {
-  // eslint-disable-next-line func-names
-  return async function () {
-    // eslint-disable-next-line prefer-rest-params
-    const args = [...arguments];
-    // Allow disabling of cache for testing purposes
-    // @ts-ignore
-    if (!InputDataService.cacheDisabled && args in storage) {
-      // @ts-ignore
-      return storage[args];
-    }
-    // @ts-ignore
-    const outcome = await func.apply(this, args);
-    // @ts-ignore
-    // eslint-disable-next-line no-param-reassign
-    storage[args] = outcome;
+    storage[cachableArgs] = outcome;
     return outcome;
   };
 }
 
 module.exports = {
   memoize,
-  memoizeAsync,
 };

packages-node/providence-analytics/src/program/utils/resolve-import-path.js

@@ -12,7 +12,7 @@
 const pathLib = require('path');
 const { nodeResolve } = require('@rollup/plugin-node-resolve');
 const { LogService } = require('../services/LogService.js');
-const { memoizeAsync } = require('./memoize.js');
+const { memoize } = require('./memoize.js');
 const { toPosixPath } = require('./to-posix-path.js');
 
 const fakePluginContext = {
@@ -64,6 +64,6 @@ async function resolveImportPath(importee, importer, opts = {}) {
  * @param {{customResolveOptions?: {preserveSymlinks:boolean}}} [opts] nodeResolve options
  * @returns {Promise<PathFromSystemRoot|null>} the resolved file system path, like '/my/project/node_modules/@lion/core/index.js'
  */
-const resolveImportPathMemoized = memoizeAsync(resolveImportPath);
+const resolveImportPathMemoized = memoize(resolveImportPath);
 
 module.exports = { resolveImportPath: resolveImportPathMemoized };

packages-node/providence-analytics/test-node/program/utils/memoize.test.js

@@ -0,0 +1,320 @@
+const { expect } = require('chai');
+const { memoize } = require('../../../src/program/utils/memoize.js');
+const { InputDataService } = require('../../../src/program/services/InputDataService.js');
+
+const cacheDisabledInitialValue = InputDataService.cacheDisabled;
+
+describe('Memoize', () => {
+  beforeEach(() => {
+    // This is important, since memoization only works
+    InputDataService.cacheDisabled = false;
+  });
+  afterEach(() => {
+    InputDataService.cacheDisabled = cacheDisabledInitialValue;
+  });
+
+  describe('With primitives', () => {
+    describe('Numbers', () => {
+      it(`returns cached result when called with same parameters`, async () => {
+        let sumCalled = 0;
+        function sum(/** @type {number} a */ a, /** @type {number} a */ b) {
+          sumCalled += 1;
+          return a + b;
+        }
+        const sumMemoized = memoize(sum);
+
+        // Put in cache for args combination
+        expect(sumMemoized(1, 2)).to.equal(3);
+        expect(sumCalled).to.equal(1);
+
+        // Return from cache
+        expect(sumMemoized(1, 2)).to.equal(3);
+        expect(sumCalled).to.equal(1);
+
+        // Put in cache for args combination
+        expect(sumMemoized(1, 3)).to.equal(4);
+        expect(sumCalled).to.equal(2);
+
+        // Return from cache
+        expect(sumMemoized(1, 3)).to.equal(4);
+        expect(sumCalled).to.equal(2);
+      });
+
+      it(`returns cached result per function for same args`, async () => {
+        let sumCalled = 0;
+        function sum(/** @type {number} a */ a, /** @type {number} a */ b) {
+          sumCalled += 1;
+          return a + b;
+        }
+        const sumMemoized = memoize(sum);
+        let sum2Called = 0;
+        function sum2(/** @type {number} a */ a, /** @type {number} a */ b) {
+          sum2Called += 1;
+          return a + b;
+        }
+        const sum2Memoized = memoize(sum2);
+
+        expect(sumMemoized(1, 2)).to.equal(3);
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(0);
+
+        expect(sum2Memoized(1, 2)).to.equal(3);
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(1);
+
+        // Both cached
+        expect(sumMemoized(1, 2)).to.equal(3);
+        expect(sum2Memoized(1, 2)).to.equal(3);
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(1);
+      });
+    });
+    describe('Strings', () => {
+      it(`returns cached result when called with same parameters`, 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);
+
+        // Put in cache for args combination
+        expect(sumMemoized('1', '3')).to.equal('13');
+        expect(sumCalled).to.equal(2);
+
+        // Return from cache
+        expect(sumMemoized('1', '3')).to.equal('13');
+        expect(sumCalled).to.equal(2);
+      });
+
+      it(`returns cached result per function for same args`, async () => {
+        let sumCalled = 0;
+        function sum(/** @type {string} a */ a, /** @type {string} a */ b) {
+          sumCalled += 1;
+          return a + b;
+        }
+        const sumMemoized = memoize(sum);
+        let sum2Called = 0;
+        function sum2(/** @type {string} a */ a, /** @type {string} a */ b) {
+          sum2Called += 1;
+          return a + b;
+        }
+        const sum2Memoized = memoize(sum2);
+
+        expect(sumMemoized('1', '2')).to.equal('12');
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(0);
+
+        expect(sum2Memoized('1', '2')).to.equal('12');
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(1);
+
+        // Both cached
+        expect(sumMemoized('1', '2')).to.equal('12');
+        expect(sum2Memoized('1', '2')).to.equal('12');
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(1);
+      });
+    });
+  });
+  describe('With non primitives', () => {
+    describe('Arrays', () => {
+      it(`returns cached result when called with same parameters`, async () => {
+        let sumCalled = 0;
+        function sum(/** @type {number[]} a */ a, /** @type {number[]} a */ b) {
+          sumCalled += 1;
+          return [...a, ...b];
+        }
+        const sumMemoized = memoize(sum);
+
+        // Put in cache for args combination
+        expect(sumMemoized([1], [2])).to.eql([1, 2]);
+        expect(sumCalled).to.equal(1);
+
+        // Return from cache
+        expect(sumMemoized([1], [2])).to.eql([1, 2]);
+        expect(sumCalled).to.equal(1);
+
+        // Put in cache for args combination
+        expect(sumMemoized([1], [3])).to.eql([1, 3]);
+        expect(sumCalled).to.equal(2);
+      });
+
+      it(`returns cached result per function for same args`, async () => {
+        let sumCalled = 0;
+        function sum(/** @type {number[]} a */ a, /** @type {number[]} a */ b) {
+          sumCalled += 1;
+          return [...a, ...b];
+        }
+        const sumMemoized = memoize(sum);
+        let sum2Called = 0;
+        function sum2(/** @type {number[]} a */ a, /** @type {number[]} a */ b) {
+          sum2Called += 1;
+          return [...a, ...b];
+        }
+        const sum2Memoized = memoize(sum2);
+
+        expect(sumMemoized([1], [2])).to.eql([1, 2]);
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(0);
+
+        expect(sum2Memoized([1], [2])).to.eql([1, 2]);
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(1);
+
+        // Both cached
+        expect(sumMemoized([1], [2])).to.eql([1, 2]);
+        expect(sum2Memoized([1], [2])).to.eql([1, 2]);
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(1);
+      });
+    });
+
+    describe('Objects', () => {
+      it(`returns cached result when called with same parameters`, async () => {
+        let sumCalled = 0;
+        function sum(/** @type {object} a */ a, /** @type {object} a */ b) {
+          sumCalled += 1;
+          return { ...a, ...b };
+        }
+        const sumMemoized = memoize(sum, { serializeObjects: true });
+
+        // Put in cache for args combination
+        expect(sumMemoized({ x: 1 }, { y: 2 })).to.eql({ x: 1, y: 2 });
+        expect(sumCalled).to.equal(1);
+
+        // Return from cache
+        expect(sumMemoized({ x: 1 }, { y: 2 })).to.eql({ x: 1, y: 2 });
+        expect(sumCalled).to.equal(1);
+
+        // Put in cache for args combination
+        expect(sumMemoized({ x: 1 }, { y: 3 })).to.eql({ x: 1, y: 3 });
+        expect(sumCalled).to.equal(2);
+      });
+
+      it(`returns cached result per function for same args`, async () => {
+        let sumCalled = 0;
+        function sum(/** @type {object} a */ a, /** @type {object} a */ b) {
+          sumCalled += 1;
+          return { ...a, ...b };
+        }
+        const sumMemoized = memoize(sum, { serializeObjects: true });
+        let sum2Called = 0;
+        function sum2(/** @type {object} a */ a, /** @type {object} a */ b) {
+          sum2Called += 1;
+          return { ...a, ...b };
+        }
+        const sum2Memoized = memoize(sum2, { serializeObjects: true });
+
+        expect(sumMemoized({ x: 1 }, { y: 2 })).to.eql({ x: 1, y: 2 });
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(0);
+
+        expect(sum2Memoized({ x: 1 }, { y: 2 })).to.eql({ x: 1, y: 2 });
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(1);
+
+        // Both cached
+        expect(sumMemoized({ x: 1 }, { y: 2 })).to.eql({ x: 1, y: 2 });
+        expect(sum2Memoized({ x: 1 }, { y: 2 })).to.eql({ x: 1, y: 2 });
+        expect(sumCalled).to.equal(1);
+        expect(sum2Called).to.equal(1);
+      });
+    });
+
+    describe('When non primitives (references) are returned', () => {
+      // Solve this by making sure your memoized function uses Object.freeze
+      it(`will be affected by edited non primitive returns`, async () => {
+        let sumCalled = 0;
+        function sum(/** @type {object} a */ a, /** @type {object} a */ b) {
+          sumCalled += 1;
+          return { ...a, ...b };
+        }
+        const sumMemoized = memoize(sum, { serializeObjects: true });
+
+        // Put in cache for args combination
+        const result = sumMemoized({ x: 1 }, { y: 2 });
+        expect(result).to.eql({ x: 1, y: 2 });
+        expect(sumCalled).to.equal(1);
+
+        // Return from cache
+        const resultCached = sumMemoized({ x: 1 }, { y: 2 });
+        expect(resultCached).to.equal(result);
+        expect(resultCached).to.eql({ x: 1, y: 2 });
+        expect(sumCalled).to.equal(1);
+
+        // Outside world can edit returned reference
+        resultCached.x = 3;
+        // Return from cache
+        const lastResult = sumMemoized({ x: 1 }, { y: 2 });
+        expect(lastResult).to.equal(result);
+        expect(lastResult).to.not.eql({ x: 1, y: 2 });
+        expect(sumCalled).to.equal(1);
+      });
+    });
+  });
+
+  describe('Asynchronous', () => {
+    it(`returns cached result when called with same parameters`, async () => {
+      let sumCalled = 0;
+      async function sum(/** @type {number} a */ a, /** @type {number} a */ b) {
+        sumCalled += 1;
+        return a + b;
+      }
+      const sumMemoized = memoize(sum);
+
+      // Put in cache for args combination
+      expect(await sumMemoized(1, 2)).to.equal(3);
+      expect(sumCalled).to.equal(1);
+
+      // Return from cache
+      expect(await sumMemoized(1, 2)).to.equal(3);
+      expect(sumCalled).to.equal(1);
+
+      // Put in cache for args combination
+      expect(await sumMemoized(1, 3)).to.equal(4);
+      expect(sumCalled).to.equal(2);
+
+      // Return from cache
+      expect(await sumMemoized(1, 3)).to.equal(4);
+      expect(sumCalled).to.equal(2);
+    });
+
+    it(`returns cached result per function for same args`, async () => {
+      let sumCalled = 0;
+      async function sum(/** @type {number} a */ a, /** @type {number} a */ b) {
+        sumCalled += 1;
+        return a + b;
+      }
+      const sumMemoized = memoize(sum);
+      let sum2Called = 0;
+      async function sum2(/** @type {number} a */ a, /** @type {number} a */ b) {
+        sum2Called += 1;
+        return a + b;
+      }
+      const sum2Memoized = memoize(sum2);
+
+      expect(await sumMemoized(1, 2)).to.equal(3);
+      expect(sumCalled).to.equal(1);
+      expect(sum2Called).to.equal(0);
+
+      expect(await sum2Memoized(1, 2)).to.equal(3);
+      expect(sumCalled).to.equal(1);
+      expect(sum2Called).to.equal(1);
+
+      // Both cached
+      expect(await sumMemoized(1, 2)).to.equal(3);
+      expect(await sum2Memoized(1, 2)).to.equal(3);
+      expect(sumCalled).to.equal(1);
+      expect(sum2Called).to.equal(1);
+    });
+  });
+});