memoizer

packages/sushi/package.json

@@ -202,6 +202,7 @@
     "date-fns": "3.3.1",
     "decimal.js-light": "2.5.1",
     "lodash.flatmap": "4.5.0",
+    "memoize-fs": "github:rouzwelt/memoize-fs#e5fcc9f6effc4ad087514372a53a49d380520ad5",
     "numbro": "2.5.0",
     "seedrandom": "3.0.5",
     "serialijse": "0.3.0",

packages/sushi/src/router/memoizer.test.ts

@@ -0,0 +1,53 @@
+import fs from 'fs'
+import { describe, expect, it } from 'vitest'
+import { memoizer } from './memoizer.js'
+
+describe('Memoizer', async () => {
+  it('should serialize, memoize, read from cache, deserialize', async () => {
+    let didHitCacheOnce = false
+    const testFn = (value1: any) => {
+      didHitCacheOnce = !didHitCacheOnce
+      return {
+        ...value1,
+        someOtherValue: 'some data',
+      }
+    }
+    const testMemoizer = await memoizer.fn(testFn)
+
+    const testValue = {
+      bigint: 12345n,
+      string: 'some text',
+      number: 123,
+      bool: true,
+      obj: {
+        prop: 'some prop',
+      },
+    }
+    const noCacheHitReturnedValue = await testMemoizer(testValue)
+    const cacheHitReturnedValue = await testMemoizer(testValue)
+    const expectedReturnedValue = {
+      bigint: 12345n,
+      string: 'some text',
+      number: 123,
+      bool: true,
+      obj: {
+        prop: 'some prop',
+      },
+      someOtherValue: 'some data',
+    }
+
+    expect(didHitCacheOnce).toEqual(true)
+    expect(noCacheHitReturnedValue).toStrictEqual(expectedReturnedValue)
+    expect(cacheHitReturnedValue).toStrictEqual(expectedReturnedValue)
+
+    // read cached file content
+    const cacheFileContent = fs.readFileSync(
+      `./mem-cache/${fs.readdirSync('./mem-cache')[0]}`,
+      { encoding: 'utf-8' },
+    )
+    const expectedCachedContent =
+      '{"data":{"bigint":"12345n","string":"some text","number":123,"bool":true,"obj":{"prop":"some prop"},"someOtherValue":"some data"}}'
+
+    expect(cacheFileContent).toEqual(expectedCachedContent)
+  })
+})

packages/sushi/src/router/memoizer.ts

@@ -0,0 +1,34 @@
+import memoize from 'memoize-fs'
+
+const serialize = (val: any) => {
+  const circRefColl: any[] = []
+  return JSON.stringify(val, (_name, value) => {
+    if (typeof value === 'function') {
+      return // ignore arguments and attributes of type function silently
+    }
+    if (typeof value === 'object' && value !== null) {
+      if (circRefColl.indexOf(value) !== -1) {
+        // circular reference has been found, discard key
+        return
+      }
+      // store value in collection
+      circRefColl.push(value)
+    }
+    if (typeof value === 'bigint') return `${value.toString()}n`
+    return value
+  })
+}
+
+const deserialize = (val: string) => {
+  return JSON.parse(val, (_key, value) => {
+    if (typeof value === 'string' && /^\d+n$/.test(value)) {
+      return BigInt(value.slice(0, -1))
+    } else return value
+  }).data
+}
+
+export const memoizer = memoize({
+  cachePath: './mem-cache',
+  serialize,
+  deserialize,
+})