From fbe4f1f37e6e2f51855bff1ffba552c6739dc7f1 Mon Sep 17 00:00:00 2001
From: Huafu Gandon <huafu.gandon@gmail.com>
Date: Thu, 26 Jul 2018 11:42:10 +0200
Subject: [PATCH] perf: do not hash cache key, jest does it underneath

---
 package.json               |  3 ++-
 src/utils/constants.ts     |  1 +
 src/utils/get-babel-rc.ts  |  1 -
 src/utils/get-cache-key.ts | 27 ++++++++++-----------------
 4 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/package.json b/package.json
index a76fa67e3a..88540da339 100644
--- a/package.json
+++ b/package.json
@@ -78,7 +78,8 @@
   },
   "peerDependencies": {
     "babel-core": "^7.0.0-0",
-    "jest": "^23.0.0 || ^24.0.0",
+    "babel-jest": "^23.0.0",
+    "jest": "^23.0.0",
     "typescript": "2.x"
   },
   "devDependencies": {
diff --git a/src/utils/constants.ts b/src/utils/constants.ts
index b8556ac8ac..675384cd92 100644
--- a/src/utils/constants.ts
+++ b/src/utils/constants.ts
@@ -9,4 +9,5 @@ export const TSCONFIG_GLOBALS_KEY = 'ts-jest';
 export const PACKAGE_JSON = 'package.json';
 export const MY_PACKAGE_CONTENT = readFileSync(
   resolve(__dirname, '..', '..', PACKAGE_JSON),
+  'utf8',
 );
diff --git a/src/utils/get-babel-rc.ts b/src/utils/get-babel-rc.ts
index c49e799531..0e7b665102 100644
--- a/src/utils/get-babel-rc.ts
+++ b/src/utils/get-babel-rc.ts
@@ -6,7 +6,6 @@ import {
   PACKAGE_JSON,
   BABEL_CONFIG_KEY,
 } from './constants';
-import { BabelTransformOptions } from '../types';
 
 const babelReaders = [
   {
diff --git a/src/utils/get-cache-key.ts b/src/utils/get-cache-key.ts
index b6a969d51a..f213e31923 100644
--- a/src/utils/get-cache-key.ts
+++ b/src/utils/get-cache-key.ts
@@ -1,4 +1,3 @@
-import { createHash } from 'crypto';
 import { JestCacheKeyOptions } from '../types';
 import { relative } from 'path';
 import { MY_PACKAGE_CONTENT } from './constants';
@@ -14,20 +13,14 @@ export default function getCacheKey(
   const jestConfig: jest.ProjectConfig = JSON.parse(jestConfigString) || {};
   delete jestConfig.cacheDirectory;
   delete jestConfig.name;
-  const hash = createHash('md5')
-    .update(MY_PACKAGE_CONTENT)
-    .update('\0', 'utf8')
-    .update(fileData)
-    .update('\0', 'utf8')
-    .update(relative(rootDir, filePath))
-    .update('\0', 'utf8')
-    .update(jestConfigString)
-    .update('\0', 'utf8')
-    .update(JSON.stringify(getTSConfig(jestConfig)))
-    .update('\0', 'utf8');
-  const babelRc = getBabelRC(filePath);
-  if (babelRc) {
-    hash.update(JSON.stringify(babelRc)).update('\0', 'utf8');
-  }
-  return hash.update(instrument ? 'instrument' : '').digest('hex');
+  // jest creates hash under the hoods
+  return JSON.stringify([
+    MY_PACKAGE_CONTENT,
+    fileData,
+    relative(rootDir, filePath),
+    jestConfig,
+    getTSConfig(jestConfig),
+    getBabelRC(filePath),
+    instrument,
+  ]);
 }