From 3cfdf706afa37c8e77187090c6b0d641e3b0c53a Mon Sep 17 00:00:00 2001
From: Daniel Roe <daniel@roe.dev>
Date: Mon, 26 Sep 2022 11:34:51 +0100
Subject: [PATCH 1/2] perf: cache package.json + tsconfig.json results

---
 src/index.ts | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index 5366eff..a2e7b90 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -9,6 +9,7 @@ export * from './types'
 export * from './utils'
 
 export type ResolveOptions = _ResolveOptions & FindFileOptions
+export type ReadOptions = { cache?: boolean }
 
 export function definePackageJSON (pkg: PackageJson): PackageJson {
   return pkg
@@ -18,21 +19,33 @@ export function defineTSConfig (tsconfig: TSConfig): TSConfig {
   return tsconfig
 }
 
-export async function readPackageJSON (id?: string, opts: ResolveOptions = {}): Promise<PackageJson> {
+const FileCache = new Map<string, Record<string, any>>()
+
+export async function readPackageJSON (id?: string, opts: ResolveOptions & ReadOptions = {}): Promise<PackageJson> {
   const resolvedPath = await resolvePackageJSON(id, opts)
+  if (opts.cache && FileCache.has(resolvedPath)) {
+    return FileCache.get(resolvedPath)!
+  }
   const blob = await fsp.readFile(resolvedPath, 'utf-8')
-  return JSON.parse(blob) as PackageJson
+  const parsed = JSON.parse(blob) as PackageJson
+  FileCache.set(resolvedPath, parsed)
+  return parsed
 }
 
 export async function writePackageJSON (path: string, pkg: PackageJson): Promise<void> {
   await fsp.writeFile(path, JSON.stringify(pkg, null, 2))
 }
 
-export async function readTSConfig (id?: string, opts: ResolveOptions = {}): Promise<TSConfig> {
+export async function readTSConfig (id?: string, opts: ResolveOptions & ReadOptions = {}): Promise<TSConfig> {
   const resolvedPath = await resolveTSConfig(id, opts)
+  if (opts.cache && FileCache.has(resolvedPath)) {
+    return FileCache.get(resolvedPath)!
+  }
   const blob = await fsp.readFile(resolvedPath, 'utf-8')
   const jsonc = await import('jsonc-parser')
-  return jsonc.parse(blob) as TSConfig
+  const parsed = jsonc.parse(blob) as TSConfig
+  FileCache.set(resolvedPath, parsed)
+  return parsed
 }
 
 export async function writeTSConfig (path: string, tsconfig: TSConfig): Promise<void> {

From f62cf5e9824eda2939b66dd1d0a8fdf592ca2806 Mon Sep 17 00:00:00 2001
From: Daniel Roe <daniel@roe.dev>
Date: Mon, 26 Sep 2022 14:01:07 +0100
Subject: [PATCH 2/2] feat: support passing user cache

---
 src/index.ts | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/index.ts b/src/index.ts
index a2e7b90..40bc0ef 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -9,7 +9,7 @@ export * from './types'
 export * from './utils'
 
 export type ResolveOptions = _ResolveOptions & FindFileOptions
-export type ReadOptions = { cache?: boolean }
+export type ReadOptions = { cache?: boolean | Map<string, Record<string, any>> }
 
 export function definePackageJSON (pkg: PackageJson): PackageJson {
   return pkg
@@ -23,12 +23,13 @@ const FileCache = new Map<string, Record<string, any>>()
 
 export async function readPackageJSON (id?: string, opts: ResolveOptions & ReadOptions = {}): Promise<PackageJson> {
   const resolvedPath = await resolvePackageJSON(id, opts)
-  if (opts.cache && FileCache.has(resolvedPath)) {
-    return FileCache.get(resolvedPath)!
+  const cache = opts.cache && typeof opts.cache !== 'boolean' ? opts.cache : FileCache
+  if (opts.cache && cache.has(resolvedPath)) {
+    return cache.get(resolvedPath)!
   }
   const blob = await fsp.readFile(resolvedPath, 'utf-8')
   const parsed = JSON.parse(blob) as PackageJson
-  FileCache.set(resolvedPath, parsed)
+  cache.set(resolvedPath, parsed)
   return parsed
 }
 
@@ -38,13 +39,14 @@ export async function writePackageJSON (path: string, pkg: PackageJson): Promise
 
 export async function readTSConfig (id?: string, opts: ResolveOptions & ReadOptions = {}): Promise<TSConfig> {
   const resolvedPath = await resolveTSConfig(id, opts)
-  if (opts.cache && FileCache.has(resolvedPath)) {
-    return FileCache.get(resolvedPath)!
+  const cache = opts.cache && typeof opts.cache !== 'boolean' ? opts.cache : FileCache
+  if (opts.cache && cache.has(resolvedPath)) {
+    return cache.get(resolvedPath)!
   }
   const blob = await fsp.readFile(resolvedPath, 'utf-8')
   const jsonc = await import('jsonc-parser')
   const parsed = jsonc.parse(blob) as TSConfig
-  FileCache.set(resolvedPath, parsed)
+  cache.set(resolvedPath, parsed)
   return parsed
 }