From 27a1a2b61908bd0a525650a59952cb377fe8707b Mon Sep 17 00:00:00 2001
From: Aravind Reddy V <zerodividedby0@gmail.com>
Date: Fri, 6 Aug 2021 23:42:32 +0530
Subject: [PATCH] in-memory memoize hash

---
 img.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/img.js b/img.js
index 1dcfeab..4762a05 100644
--- a/img.js
+++ b/img.js
@@ -122,7 +122,10 @@ function getValidWidths(originalWidth, widths = [], allowUpscale = false) {
   return filtered.sort((a, b) => a - b);
 }
 
+let imgHashCache = {};
 function getHash(src, imgOptions={}, length=10) {
+  if(src in imgHashCache) return imgHashCache[src];
+  
   const hash = createHash("sha256");
 
   let opts = Object.assign({
@@ -151,7 +154,9 @@ function getHash(src, imgOptions={}, length=10) {
   }
 
   hash.update(JSON.stringify(opts));
-  return hash.digest("base64url").substring(0, length);;
+  imgHashCache[src] = hash.digest("base64url").substring(0, length);
+
+  return imgHashCache[src];
 }
 
 function getFilename(src, width, format, options = {}) {