From: Chris Duncan <chris@codecow.com>
Date: Fri, 22 May 2026 18:27:31 +0000 (-0700)
Subject: Extract equivalence test for cached work.
X-Git-Url: https://git.codecow.com/?a=commitdiff_plain;h=ea835367660946dfa37f1fa68361601bc82c75ad;p=nano-pow.git

Extract equivalence test for cached work.
---

diff --git a/src/utils/cache.ts b/src/utils/cache.ts
index 779a227..6e86a3f 100644
--- a/src/utils/cache.ts
+++ b/src/utils/cache.ts
@@ -5,7 +5,13 @@ import { WorkGenerateResponse } from 'nano-pow'
 
 const STORAGE_KEY = 'NanoPowCache'
 
-let storage: { [key: string]: string } = {}
+let storage: Record<string, string> = {}
+
+function eq (a: unknown, b: bigint): boolean {
+	return typeof a === 'string'
+		&& /^([a-f0-9]{2})+$/i.test(a)
+		&& BigInt(`0x${a}`) === b
+}
 
 function getItem (key: string): string | null {
 	if (globalThis?.localStorage) return globalThis.localStorage.getItem(key)
@@ -30,12 +36,8 @@ export function get (hash: bigint, difficulty: bigint): WorkGenerateResponse | n
 	const item = getItem(STORAGE_KEY)
 	if (item == null) return null
 	const cache: WorkGenerateResponse[] = JSON.parse(item)
-	for (const c of cache) {
-		if (BigInt(`0x${c.hash}`) === hash && BigInt(`0x${c.difficulty}`) >= difficulty) {
-			return c
-		}
-	}
-	return null
+	const match = cache.find(c => eq(c.hash, hash) && eq(c.difficulty, difficulty))
+	return match ?? null
 }
 
 export function remove (hash: bigint): void {
@@ -43,11 +45,11 @@ export function remove (hash: bigint): void {
 	if (item == null) return
 	const cache = JSON.parse(item) as WorkGenerateResponse[]
 	for (let i = 0; i < cache.length; i++) {
-		if (BigInt(`0x${cache[i].hash}`) === hash) {
+		if (eq(cache[i].hash, hash)) {
 			cache.splice(i, 1)
 		}
 	}
-	setItem('NanoPowCache', JSON.stringify(cache))
+	setItem(STORAGE_KEY, JSON.stringify(cache))
 }
 
 export function set (result: WorkGenerateResponse): WorkGenerateResponse {