From c1f43cb972bacd9cd8d8e55207abca9585847581 Mon Sep 17 00:00:00 2001
From: Aarni Koskela <akx@iki.fi>
Date: Fri, 10 Feb 2017 15:54:06 +0200
Subject: [PATCH] Cache resolve-rc results

---
 src/fs-cache.js   | 4 ++--
 src/resolve-rc.js | 8 +++++++-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/fs-cache.js b/src/fs-cache.js
index 206c74a3..05b77130 100644
--- a/src/fs-cache.js
+++ b/src/fs-cache.js
@@ -15,6 +15,8 @@ const os = require("os");
 const path = require("path");
 const zlib = require("zlib");
 
+let defaultCacheDirectory = null;  // Lazily instantiated when needed
+
 /**
  * Read the contents from the compressed file.
  *
@@ -162,8 +164,6 @@ const handleCache = function(directory, params, callback) {
  *   });
  */
 
-var defaultCacheDirectory = null;  // Lazily instantiated when needed
-
 module.exports = function(params, callback) {
   let directory;
 
diff --git a/src/resolve-rc.js b/src/resolve-rc.js
index 30b84f8b..504ce8f2 100644
--- a/src/resolve-rc.js
+++ b/src/resolve-rc.js
@@ -10,6 +10,8 @@ const path = require("path");
 const exists = require("./utils/exists")({});
 const read = require("./utils/read")({});
 
+const cache = {};
+
 const find = function find(start, rel) {
   const file = path.join(start, rel);
 
@@ -27,6 +29,10 @@ const find = function find(start, rel) {
 
 module.exports = function(loc, rel) {
   rel = rel || ".babelrc";
+  const cacheKey = "" + loc + "/" + rel;
+  if (cacheKey in cache) {
+    return cache[cacheKey];
+  }
 
-  return find(loc, rel);
+  return (cache[cacheKey] = find(loc, rel));
 };