feat(typescript-estree): expose a wrapper cache clearing function for advanced usecases

.gitignore

@@ -76,6 +76,7 @@ jspm_packages/
 .idea
 dist
 _ts3.4
+_ts4.2
 *.tsbuildinfo
 .watchmanconfig
 .rollup.cache

packages/typescript-estree/src/clear-caches.ts

@@ -0,0 +1,21 @@
+import { clearWatchCaches } from './create-program/getWatchProgramsForProjects';
+import { clearProgramCache as clearProgramCacheOriginal } from './parser';
+import { clearTSConfigMatchCache } from './parseSettings/createParseSettings';
+import { clearGlobCache } from './parseSettings/resolveProjectList';
+
+/**
+ * Clears all of the internal caches.
+ * Generally you shouldn't need or want to use this.
+ * Examples of intended uses:
+ * - In tests to reset parser state to keep tests isolated.
+ * - In custom lint tooling that iteratively lints one project at a time to prevent OOMs.
+ */
+export function clearCaches(): void {
+  clearProgramCacheOriginal();
+  clearWatchCaches();
+  clearTSConfigMatchCache();
+  clearGlobCache();
+}
+
+// TODO - delete this in next major
+export const clearProgramCache = clearCaches();

packages/typescript-estree/src/index.ts

@@ -5,16 +5,15 @@ export {
   parseWithNodeMaps,
   ParseAndGenerateServicesResult,
   ParseWithNodeMapsResult,
-  clearProgramCache,
 } from './parser';
 export { ParserServices, TSESTreeOptions } from './parser-options';
 export { simpleTraverse } from './simple-traverse';
 export * from './ts-estree';
-export { clearWatchCaches as clearCaches } from './create-program/getWatchProgramsForProjects';
 export { createProgramFromConfigFile as createProgram } from './create-program/useProvidedPrograms';
 export * from './create-program/getScriptKind';
 export { typescriptVersionIsAtLeast } from './version-check';
 export * from './getModifiers';
+export * from './clear-caches';
 
 // re-export for backwards-compat
 export { visitorKeys } from '@typescript-eslint/visitor-keys';

packages/typescript-estree/src/parseSettings/createParseSettings.ts

@@ -121,6 +121,10 @@ export function createParseSettings(
   return parseSettings;
 }
 
+export function clearTSConfigMatchCache(): void {
+  TSCONFIG_MATCH_CACHE?.clear();
+}
+
 /**
  * Ensures source code is a string.
  */

packages/typescript-estree/src/parseSettings/resolveProjectList.ts

@@ -21,6 +21,10 @@ const log = debug(
 let RESOLUTION_CACHE: ExpiringCache<string, readonly CanonicalPath[]> | null =
   null;
 
+export function clearGlobCache(): void {
+  RESOLUTION_CACHE?.clear();
+}
+
 /**
  * Normalizes, sanitizes, resolves and filters the provided project paths
  */