feat(typescript-estree): add parserOption to turn on debug logs

packages/experimental-utils/src/ts-eslint/ParserOptions.ts

@@ -1,3 +1,5 @@
+import { DebugLevel } from '@typescript-eslint/typescript-estree';
+
 export interface ParserOptions {
   comment?: boolean;
   ecmaFeatures?: {
@@ -9,6 +11,7 @@ export interface ParserOptions {
   errorOnUnknownASTType?: boolean;
   extraFileExtensions?: string[];
   // ts-estree specific
+  debugLevel?: DebugLevel;
   filePath?: string;
   loc?: boolean;
   noWatch?: boolean;

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

@@ -3,9 +3,9 @@ import path from 'path';
 import * as ts from 'typescript';
 import { Extra } from '../parser-options';
 import {
-  getTsconfigPath,
-  DEFAULT_COMPILER_OPTIONS,
   ASTAndProgram,
+  getTsconfigPath,
+  createDefaultCompilerOptionsFromExtra,
 } from './shared';
 
 const log = debug('typescript-eslint:typescript-estree:createDefaultProgram');
@@ -31,7 +31,7 @@ function createDefaultProgram(
 
   const commandLine = ts.getParsedCommandLineOfConfigFile(
     tsconfigPath,
-    DEFAULT_COMPILER_OPTIONS,
+    createDefaultCompilerOptionsFromExtra(extra),
     { ...ts.sys, onUnRecoverableConfigFileDiagnostic: () => {} },
   );
 

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

@@ -3,7 +3,7 @@ import * as ts from 'typescript';
 import { Extra } from '../parser-options';
 import {
   ASTAndProgram,
-  DEFAULT_COMPILER_OPTIONS,
+  createDefaultCompilerOptionsFromExtra,
   getScriptKind,
 } from './shared';
 
@@ -67,7 +67,7 @@ function createIsolatedProgram(code: string, extra: Extra): ASTAndProgram {
       noResolve: true,
       target: ts.ScriptTarget.Latest,
       jsx: extra.jsx ? ts.JsxEmit.Preserve : undefined,
-      ...DEFAULT_COMPILER_OPTIONS,
+      ...createDefaultCompilerOptionsFromExtra(extra),
     },
     compilerHost,
   );

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

@@ -6,9 +6,9 @@ import { WatchCompilerHostOfConfigFile } from './WatchCompilerHostOfConfigFile';
 import {
   canonicalDirname,
   CanonicalPath,
-  getTsconfigPath,
-  DEFAULT_COMPILER_OPTIONS,
+  createDefaultCompilerOptionsFromExtra,
   getCanonicalFileName,
+  getTsconfigPath,
 } from './shared';
 
 const log = debug('typescript-eslint:typescript-estree:createWatchProgram');
@@ -233,7 +233,7 @@ function createWatchProgram(
   // create compiler host
   const watchCompilerHost = ts.createWatchCompilerHost(
     tsconfigPath,
-    DEFAULT_COMPILER_OPTIONS,
+    createDefaultCompilerOptionsFromExtra(extra),
     ts.sys,
     ts.createSemanticDiagnosticsBuilderProgram,
     diagnosticReporter,

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

@@ -20,6 +20,19 @@ const DEFAULT_COMPILER_OPTIONS: ts.CompilerOptions = {
   noUnusedParameters: true,
 };
 
+function createDefaultCompilerOptionsFromExtra(
+  extra: Extra,
+): ts.CompilerOptions {
+  if (extra.debugLevel.has('typescript')) {
+    return {
+      ...DEFAULT_COMPILER_OPTIONS,
+      extendedDiagnostics: true,
+    };
+  }
+
+  return DEFAULT_COMPILER_OPTIONS;
+}
+
 // This narrows the type so we can be sure we're passing canonical names in the correct places
 type CanonicalPath = string & { __brand: unknown };
 
@@ -83,7 +96,7 @@ export {
   ASTAndProgram,
   canonicalDirname,
   CanonicalPath,
-  DEFAULT_COMPILER_OPTIONS,
+  createDefaultCompilerOptionsFromExtra,
   getCanonicalFileName,
   getScriptKind,
   getTsconfigPath,

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

@@ -1,11 +1,25 @@
 import { Program } from 'typescript';
 import { TSESTree, TSNode } from './ts-estree';
 
+type DebugModule = 'typescript-eslint' | 'eslint' | 'typescript';
+/**
+ * For convenience:
+ * - true === ['typescript-eslint']
+ * - false === []
+ *
+ * An array of modules to turn explicit debugging on for.
+ * - 'typescript-eslint' is the same as setting the env var `DEBUG=typescript-eslint:*`
+ * - 'eslint' is the same as setting the env var `DEBUG=eslint:*`
+ * - 'typescript' is the same as setting `extendedDiagnostics: true` in your tsconfig compilerOptions
+ */
+export type DebugLevel = boolean | DebugModule[];
+
 export interface Extra {
   code: string;
   comment: boolean;
   comments: TSESTree.Comment[];
   createDefaultProgram: boolean;
+  debugLevel: Set<DebugModule>;
   errorOnTypeScriptSyntacticAndSemanticIssues: boolean;
   errorOnUnknownASTType: boolean;
   extraFileExtensions: string[];
@@ -25,6 +39,7 @@ export interface Extra {
 export interface TSESTreeOptions {
   comment?: boolean;
   createDefaultProgram?: boolean;
+  debugLevel?: DebugLevel;
   errorOnTypeScriptSyntacticAndSemanticIssues?: boolean;
   errorOnUnknownASTType?: boolean;
   extraFileExtensions?: string[];

packages/typescript-estree/src/parser.ts

@@ -1,7 +1,8 @@
-import semver from 'semver';
-import * as ts from 'typescript';
+import debug from 'debug';
 import { sync as globSync } from 'glob';
 import isGlob from 'is-glob';
+import semver from 'semver';
+import * as ts from 'typescript';
 import { astConverter } from './ast-converter';
 import { convertError } from './convert';
 import { createDefaultProgram } from './create-program/createDefaultProgram';
@@ -91,6 +92,7 @@ function resetExtra(): void {
     comment: false,
     comments: [],
     createDefaultProgram: false,
+    debugLevel: new Set(),
     errorOnTypeScriptSyntacticAndSemanticIssues: false,
     errorOnUnknownASTType: false,
     extraFileExtensions: [],
@@ -109,6 +111,31 @@ function resetExtra(): void {
 }
 
 function applyParserOptionsToExtra(options: TSESTreeOptions): void {
+  /**
+   * Configure Debug logging
+   */
+  if (options.debugLevel === true) {
+    extra.debugLevel = new Set(['typescript-eslint']);
+  } else if (Array.isArray(options.debugLevel)) {
+    extra.debugLevel = new Set(options.debugLevel);
+  }
+  if (extra.debugLevel.size > 0) {
+    // debug doesn't support multiple `enable` calls, so have to do it all at once
+    const namespaces = [];
+    if (extra.debugLevel.has('typescript-eslint')) {
+      namespaces.push('typescript-eslint:*');
+    }
+    if (
+      extra.debugLevel.has('eslint') ||
+      // make sure we don't turn off the eslint debug if it was enabled via --debug
+      debug.enabled('eslint:*')
+    ) {
+      // https://github.com/eslint/eslint/blob/9dfc8501fb1956c90dc11e6377b4cb38a6bea65d/bin/eslint.js#L25
+      namespaces.push('eslint:*,-eslint:code-path');
+    }
+    debug.enable(namespaces.join(','));
+  }
+
   /**
    * Track range information in the AST
    */
@@ -415,10 +442,9 @@ export {
   parse,
   parseAndGenerateServices,
   ParseAndGenerateServicesResult,
-  ParserServices,
-  TSESTreeOptions,
   version,
 };
+export { DebugLevel, ParserServices, TSESTreeOptions } from './parser-options';
 export { simpleTraverse } from './simple-traverse';
 export { visitorKeys } from './visitor-keys';
 export * from './ts-estree';