fix(jest-resolve): cache package.json lookups

packages/jest-resolve/package.json

@@ -20,7 +20,7 @@
     "graceful-fs": "^4.2.4",
     "jest-pnp-resolver": "^1.2.2",
     "jest-util": "^27.0.0-next.1",
-    "resolve": "^1.18.1",
+    "resolve": "^1.20.0",
     "slash": "^3.0.0"
   },
   "devDependencies": {

packages/jest-resolve/src/defaultResolver.ts

@@ -50,6 +50,8 @@ export default function defaultResolver(
     packageFilter: options.packageFilter,
     paths: options.paths,
     preserveSymlinks: false,
+    // @ts-expect-error: https://github.com/DefinitelyTyped/DefinitelyTyped/pull/51182
+    readPackageSync,
     realpathSync,
   });
 
@@ -61,6 +63,7 @@ export default function defaultResolver(
 export function clearDefaultResolverCache(): void {
   checkedPaths.clear();
   checkedRealpathPaths.clear();
+  packageContents.clear();
 }
 
 enum IPathType {
@@ -118,6 +121,21 @@ function realpathCached(path: Config.Path): Config.Path {
   return result;
 }
 
+const packageContents = new Map<string, unknown>();
+function readPackageCached(path: Config.Path): unknown {
+  let result = packageContents.get(path);
+
+  if (result !== undefined) {
+    return result;
+  }
+
+  result = JSON.parse(fs.readFileSync(path, 'utf8'));
+
+  packageContents.set(path, result);
+
+  return result;
+}
+
 /*
  * helper functions
  */
@@ -132,3 +150,7 @@ function isDirectory(dir: Config.Path): boolean {
 function realpathSync(file: Config.Path): Config.Path {
   return realpathCached(file);
 }
+
+function readPackageSync(_: unknown, file: Config.Path): unknown {
+  return readPackageCached(file);
+}

yarn.lock

@@ -9402,11 +9402,11 @@ fsevents@^1.2.7:
   linkType: hard
 
 fsevents@^2.2.1:
-  version: 2.3.1
-  resolution: "fsevents@npm:2.3.1"
+  version: 2.3.2
+  resolution: "fsevents@npm:2.3.2"
   dependencies:
     node-gyp: latest
-  checksum: 32619a121e7f9ac8a5ce4954f5fdf06be68b7b1c16e4ac8fa6e5e13cbf97d83c86cdcdf872ab7b188ebb07b34d2271b7818aebfc305b4a7d5b35f4bc2117f8be
+  checksum: a1883f4ca12b8b403ec528f1a4cb312b0877eacd24719da535cabea78d6fdd78530e3538bdba590a1c0f6c295128f964a89182621885296353a44dcfa4f9db53
   languageName: node
   linkType: hard
 
@@ -9421,11 +9421,11 @@ fsevents@^2.2.1:
   linkType: hard
 
 "fsevents@patch:fsevents@^2.2.1#builtin<compat/fsevents>":
-  version: 2.3.1
-  resolution: "fsevents@patch:fsevents@npm%3A2.3.1#builtin<compat/fsevents>::version=2.3.1&hash=11e9ea"
+  version: 2.3.2
+  resolution: "fsevents@patch:fsevents@npm%3A2.3.2#builtin<compat/fsevents>::version=2.3.2&hash=11e9ea"
   dependencies:
     node-gyp: latest
-  checksum: 66b24358e15cdd0f705b456346e58b4613f2bf54206b47874decda4152614fb0632d2d662c92b0ea54810109f646e5233e4cdd64dbb2a1949070ee5dc14dab87
+  checksum: 7b25d9251aefe433d508a0eb614217f0495ae05a9e8af15f7dbf9998e08c4e675acd1cf32361e0fcf71d917d9e8c4b76301fdc72a1ec1105a3ea0994f5e15a8d
   languageName: node
   linkType: hard
 
@@ -10931,7 +10931,7 @@ fsevents@~2.1.2:
   languageName: node
   linkType: hard
 
-"is-core-module@npm:^2.1.0":
+"is-core-module@npm:^2.2.0":
   version: 2.2.0
   resolution: "is-core-module@npm:2.2.0"
   dependencies:
@@ -12041,7 +12041,7 @@ fsevents@~2.1.2:
     jest-haste-map: ^27.0.0-next.2
     jest-pnp-resolver: ^1.2.2
     jest-util: ^27.0.0-next.1
-    resolve: ^1.18.1
+    resolve: ^1.20.0
     slash: ^3.0.0
   languageName: unknown
   linkType: soft
@@ -17345,23 +17345,23 @@ react-native@0.63.2:
   languageName: node
   linkType: hard
 
-"resolve@^1.1.6, resolve@^1.10.0, resolve@^1.13.1, resolve@^1.15.0, resolve@^1.17.0, resolve@^1.18.1, resolve@^1.3.2, resolve@^1.5.0, resolve@^1.8.1":
-  version: 1.19.0
-  resolution: "resolve@npm:1.19.0"
+"resolve@^1.1.6, resolve@^1.10.0, resolve@^1.13.1, resolve@^1.15.0, resolve@^1.17.0, resolve@^1.20.0, resolve@^1.3.2, resolve@^1.5.0, resolve@^1.8.1":
+  version: 1.20.0
+  resolution: "resolve@npm:1.20.0"
   dependencies:
-    is-core-module: ^2.1.0
+    is-core-module: ^2.2.0
     path-parse: ^1.0.6
-  checksum: 8b23c7fde1224898ffb9fec2a2295a44d1564981343bdbf5fd3769465658f6a6f6647bb7ea66dfb3c1291ca86046b0233be2edfcd8ca05b38886521e8869677c
+  checksum: 0f5206d454b30e74d9b2d575b5f8aedf443c4d8b90b84cdf79474ade29bb459075220da3127b682896872a16022ed65cc4db09e0f23849654144d3d75c65cd1b
   languageName: node
   linkType: hard
 
-"resolve@patch:resolve@^1.1.6#builtin<compat/resolve>, resolve@patch:resolve@^1.10.0#builtin<compat/resolve>, resolve@patch:resolve@^1.13.1#builtin<compat/resolve>, resolve@patch:resolve@^1.15.0#builtin<compat/resolve>, resolve@patch:resolve@^1.17.0#builtin<compat/resolve>, resolve@patch:resolve@^1.18.1#builtin<compat/resolve>, resolve@patch:resolve@^1.3.2#builtin<compat/resolve>, resolve@patch:resolve@^1.5.0#builtin<compat/resolve>, resolve@patch:resolve@^1.8.1#builtin<compat/resolve>":
-  version: 1.19.0
-  resolution: "resolve@patch:resolve@npm%3A1.19.0#builtin<compat/resolve>::version=1.19.0&hash=3388aa"
+"resolve@patch:resolve@^1.1.6#builtin<compat/resolve>, resolve@patch:resolve@^1.10.0#builtin<compat/resolve>, resolve@patch:resolve@^1.13.1#builtin<compat/resolve>, resolve@patch:resolve@^1.15.0#builtin<compat/resolve>, resolve@patch:resolve@^1.17.0#builtin<compat/resolve>, resolve@patch:resolve@^1.20.0#builtin<compat/resolve>, resolve@patch:resolve@^1.3.2#builtin<compat/resolve>, resolve@patch:resolve@^1.5.0#builtin<compat/resolve>, resolve@patch:resolve@^1.8.1#builtin<compat/resolve>":
+  version: 1.20.0
+  resolution: "resolve@patch:resolve@npm%3A1.20.0#builtin<compat/resolve>::version=1.20.0&hash=3388aa"
   dependencies:
-    is-core-module: ^2.1.0
+    is-core-module: ^2.2.0
     path-parse: ^1.0.6
-  checksum: 188d5167e8578a9af8d194faf382b8f3526aad5145391c24ecdc6246c6fc82c10fc66d6352267f8e93c5977c503d61803169c91b9e2ee36dd2de759915c9b673
+  checksum: c4a515b76026806b5b26513fc7bdb80458c532bc91c02ef45ac928d1025585f93bec0b904be39c02131118a37ff7e3f9258f1526850b025d2ec0948bb5fd03d0
   languageName: node
   linkType: hard