feat(typescript-estree): allow specifying project: true

packages/eslint-plugin-tslint/src/rules/config.ts

@@ -98,18 +98,13 @@ export default createRule<Options, MessageIds>({
     ],
   },
   defaultOptions: [{}],
-  create(context) {
+  create(
+    context,
+    [{ rules: tslintRules, rulesDirectory: tslintRulesDirectory, lintFile }],
+  ) {
     const fileName = context.getFilename();
     const sourceCode = context.getSourceCode().text;
     const parserServices = ESLintUtils.getParserServices(context);
-
-    /**
-     * The TSLint rules configuration passed in by the user
-     */
-    const [
-      { rules: tslintRules, rulesDirectory: tslintRulesDirectory, lintFile },
-    ] = context.options;
-
     const program = parserServices.program;
 
     /**

packages/parser/README.md

@@ -59,7 +59,7 @@ interface ParserOptions {
   jsxFragmentName?: string | null;
   lib?: string[];
 
-  project?: string | string[];
+  project?: string | string[] | true;
   projectFolderIgnoreList?: string[];
   tsconfigRootDir?: string;
   extraFileExtensions?: string[];

packages/types/src/parser-options.ts

@@ -51,7 +51,7 @@ interface ParserOptions {
   filePath?: string;
   loc?: boolean;
   program?: Program;
-  project?: string | string[];
+  project?: string | string[] | true;
   projectFolderIgnoreList?: (string | RegExp)[];
   range?: boolean;
   sourceType?: SourceType;

packages/typescript-estree/README.md

@@ -180,10 +180,11 @@ interface ParseAndGenerateServicesOptions extends ParseOptions {
   preserveNodeMaps?: boolean;
 
   /**
-   * Absolute (or relative to `tsconfigRootDir`) paths to the tsconfig(s).
+   * Absolute (or relative to `tsconfigRootDir`) paths to the tsconfig(s),
+   * or `true` to find the nearest tsconfig.json to the file.
    * If this is provided, type information will be returned.
    */
-  project?: string | string[];
+  project?: string | string[] | true;
 
   /**
    * If you provide a glob (or globs) to the project option, you can use this option to ignore certain folders from

packages/typescript-estree/src/create-program/createWatchProgram.ts

@@ -548,4 +548,4 @@ function maybeInvalidateProgram(
   return null;
 }
 
-export { clearWatchCaches, createWatchProgram, getProgramsForProjects };
+export { clearWatchCaches, getProgramsForProjects };

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

@@ -8,6 +8,7 @@ import {
   getCanonicalFileName,
 } from '../create-program/shared';
 import type { TSESTreeOptions } from '../parser-options';
+import { getProjectConfigFiles } from './getProjectConfigFiles';
 import type { MutableParseSettings } from './index';
 import { inferSingleRun } from './inferSingleRun';
 import { warnAboutTSVersion } from './warnAboutTSVersion';
@@ -112,7 +113,7 @@ export function createParseSettings(
 
     parseSettings.projects = prepareAndTransformProjects(
       tsconfigRootDir,
-      options.project,
+      getProjectConfigFiles(parseSettings, options.project),
       projectFolderIgnoreList,
     );
   }

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

@@ -0,0 +1,80 @@
+import debug from 'debug';
+import fs from 'fs';
+import path from 'path';
+
+import type { ParseSettings } from '.';
+
+const log = debug('typescript-eslint:typescript-estree:getProjectConfigFiles');
+
+interface TSConfigMatch {
+  exists: boolean;
+  timestamp: number;
+}
+
+/**
+ * How many milliseconds we will respect a cache for checking an fs.existsSync
+ * check for a file file on disk.
+ */
+const RECHECK_FILE_THRESHOLD_MS = 50;
+
+const tsconfigMatchCache = new Map<string, TSConfigMatch>();
+
+/**
+ * Checks for a file file on disk, respecting a limited-time cache.
+ * This keeps a caches checked paths with existence and `Date.now()` timestamp.
+ * After `RECHECK_FILE_THRESHOLD_MS`, cache entries are ignored.
+ *
+ * @param filePath File path to check for existence on disk.
+ * @returns Whether the file exists on disk.
+ * @remarks
+ * We don't (yet!) have a way to attach file watchers on disk, but still need to
+ * cache file checks for rapid subsequent calls to fs.existsSync. See discussion
+ * in https://github.com/typescript-eslint/typescript-eslint/issues/101.
+ */
+function existsSyncCached(filePath: string): boolean {
+  const cached = tsconfigMatchCache.get(filePath);
+  const now = Date.now();
+
+  if (cached && now - cached.timestamp < RECHECK_FILE_THRESHOLD_MS) {
+    return cached.exists;
+  }
+
+  const exists = fs.existsSync(filePath);
+
+  tsconfigMatchCache.set(filePath, {
+    exists,
+    timestamp: now,
+  });
+
+  return exists;
+}
+
+export function getProjectConfigFiles(
+  parseSettings: ParseSettings,
+  projects: string | string[] | true | undefined,
+): string | string[] | undefined {
+  if (projects !== true) {
+    return projects;
+  }
+
+  log('Looking for tsconfig.json at or above file: %s', parseSettings.filePath);
+  let directory = path.dirname(parseSettings.filePath);
+
+  do {
+    const tsconfigPath = path.join(directory, 'tsconfig.json');
+    log('Checking tsconfig.json path: %s', tsconfigPath);
+
+    if (existsSyncCached(tsconfigPath)) {
+      return [tsconfigPath];
+    }
+
+    directory = path.basename(directory);
+  } while (
+    directory &&
+    directory.length < parseSettings.tsconfigRootDir.length
+  );
+
+  throw new Error(
+    `project was set to \`true\` but couldn't find any tsconfig.json relative to '${parseSettings.filePath}' within '${parseSettings.tsconfigRootDir}.`,
+  );
+}

packages/typescript-estree/src/parser-options.ts

@@ -117,10 +117,11 @@ interface ParseAndGenerateServicesOptions extends ParseOptions {
   preserveNodeMaps?: boolean;
 
   /**
-   * Absolute (or relative to `tsconfigRootDir`) paths to the tsconfig(s).
+   * Absolute (or relative to `tsconfigRootDir`) paths to the tsconfig(s),
+   * or `true` to find the nearest tsconfig.json to the file.
    * If this is provided, type information will be returned.
    */
-  project?: string | string[];
+  project?: string | string[] | true;
 
   /**
    * If you provide a glob (or globs) to the project option, you can use this option to ignore certain folders from