From 56956dba4fd9c15217b367a99d70d4df97175a31 Mon Sep 17 00:00:00 2001
From: mike12345567 <me@michaeldrury.co.uk>
Date: Thu, 23 Jun 2022 20:27:20 +0100
Subject: [PATCH] Adding a class wrapper incase using get/put functions
 multiple times, functions like the PouchDB constructor.

---
 .../src/cache/tests/writethrough.spec.js      | 12 +++++------
 .../backend-core/src/cache/writethrough.ts    | 21 ++++++++++++++++---
 2 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/packages/backend-core/src/cache/tests/writethrough.spec.js b/packages/backend-core/src/cache/tests/writethrough.spec.js
index 6a949a7489..a0ada8b51b 100644
--- a/packages/backend-core/src/cache/tests/writethrough.spec.js
+++ b/packages/backend-core/src/cache/tests/writethrough.spec.js
@@ -1,5 +1,5 @@
 require("../../../tests/utilities/TestConfiguration")
-const { get, put } = require("../writethrough")
+const { Writethrough } = require("../writethrough")
 const { dangerousGetDB } = require("../../db")
 const tk = require("timekeeper")
 
@@ -9,20 +9,20 @@ tk.freeze(START_DATE)
 const DELAY = 5000
 
 const db = dangerousGetDB("test")
+const writethrough = new Writethrough(db)
 
 describe("writethrough", () => {
-
   describe("put", () => {
     let first
     it("should be able to store, will go to DB", async () => {
-      const response = await put(db,{ _id: "test", value: 1 }, DELAY)
+      const response = await writethrough.put({ _id: "test", value: 1 }, DELAY)
       const output = await db.get(response._id)
       first = output
       expect(output.value).toBe(1)
     })
 
     it("second put shouldn't update DB", async () => {
-      const response = await put(db, { ...first, value: 2 }, DELAY)
+      const response = await writethrough.put({ ...first, value: 2 }, DELAY)
       const output = await db.get(response._id)
       expect(first._rev).toBe(output._rev)
       expect(output.value).toBe(1)
@@ -30,7 +30,7 @@ describe("writethrough", () => {
 
     it("should put it again after delay period", async () => {
       tk.freeze(START_DATE + DELAY + 1)
-      const response = await put(db, { ...first, value: 3 }, DELAY)
+      const response = await writethrough.put({ ...first, value: 3 }, DELAY)
       const output = await db.get(response._id)
       expect(response._rev).not.toBe(first._rev)
       expect(output.value).toBe(3)
@@ -39,7 +39,7 @@ describe("writethrough", () => {
 
   describe("get", () => {
     it("should be able to retrieve", async () => {
-      const response = await get(db, "test")
+      const response = await writethrough.get("test")
       expect(response.value).toBe(3)
     })
   })
diff --git a/packages/backend-core/src/cache/writethrough.ts b/packages/backend-core/src/cache/writethrough.ts
index 85e3c9e50e..02932d0c2c 100644
--- a/packages/backend-core/src/cache/writethrough.ts
+++ b/packages/backend-core/src/cache/writethrough.ts
@@ -21,11 +21,11 @@ function makeCacheItem(value: any, lastWrite: number | null = null): CacheItem {
   return { value, lastWrite: lastWrite || Date.now() }
 }
 
-exports.put = async (
+export async function put(
   db: PouchDB.Database,
   value: any,
   writeRateMs: number = DEFAULT_WRITE_RATE_MS
-) => {
+) {
   const cache = await getCache()
   const key = value._id
   let cacheItem: CacheItem | undefined = await cache.get(key)
@@ -46,7 +46,7 @@ exports.put = async (
   return output
 }
 
-exports.get = async (db: PouchDB.Database, id: string): Promise<any> => {
+export async function get(db: PouchDB.Database, id: string): Promise<any> {
   const cache = await getCache()
   let cacheItem: CacheItem = await cache.get(id)
   if (!cacheItem) {
@@ -56,3 +56,18 @@ exports.get = async (db: PouchDB.Database, id: string): Promise<any> => {
   }
   return cacheItem.value
 }
+
+export class Writethrough {
+  db: PouchDB.Database
+  constructor(db: PouchDB.Database) {
+    this.db = db
+  }
+
+  async put(value: any, writeRateMs: number = DEFAULT_WRITE_RATE_MS) {
+    return put(this.db, value, writeRateMs)
+  }
+
+  async get(id: string) {
+    return get(this.db, id)
+  }
+}