chore(no-deprecated-functions): cache jest version

Author: G-Rath

src/rules/__tests__/no-deprecated-functions.test.ts

@@ -3,7 +3,10 @@ import * as os from 'os';
 import * as path from 'path';
 import { JSONSchemaForNPMPackageJsonFiles } from '@schemastore/package';
 import { TSESLint } from '@typescript-eslint/experimental-utils';
-import rule, { JestVersion } from '../no-deprecated-functions';
+import rule, {
+  JestVersion,
+  _clearCachedJestVersion,
+} from '../no-deprecated-functions';
 
 const ruleTester = new TSESLint.RuleTester();
 
@@ -89,6 +92,8 @@ const generateInvalidCases = (
   ];
 };
 
+beforeEach(() => _clearCachedJestVersion());
+
 // a few sanity checks before doing our massive loop
 ruleTester.run('no-deprecated-functions', rule, {
   valid: [

src/rules/no-deprecated-functions.ts

@@ -30,7 +30,16 @@ interface EslintPluginJestSettings {
   version: JestVersion;
 }
 
+let cachedJestVersion: JestVersion | null = null;
+
+/** @internal */
+export const _clearCachedJestVersion = () => (cachedJestVersion = null);
+
 const detectJestVersion = (): JestVersion => {
+  if (cachedJestVersion) {
+    return cachedJestVersion;
+  }
+
   try {
     const jestPath = require.resolve('jest/package.json', {
       paths: [process.cwd()],
@@ -42,7 +51,7 @@ const detectJestVersion = (): JestVersion => {
     if (jestPackageJson.version) {
       const [majorVersion] = jestPackageJson.version.split('.');
 
-      return parseInt(majorVersion);
+      return (cachedJestVersion = parseInt(majorVersion, 10));
     }
   } catch {}