fix: make ESLint work without a .gitignore file (#27)

Author: ShayanTheNerd

src/index.d.ts

@@ -97,10 +97,10 @@ export interface Options extends Linter.Config {
    */
   ignores?: string[];
   /**
-   * .gitignore file path relative to ESLint configuration file.
+   * .gitignore file path relative to ESLint configuration file. Set to `false` to disable.
    * @default './.gitignore'
    */
-  gitignorePath?: string;
+  gitignore?: string | false;
 }
 
 export declare function defineConfig(initOptions?: Options, ...extend: Linter.Config[]): Linter.Config[];

src/index.mjs

@@ -33,7 +33,7 @@ const defaultOptions = {
   disableExpensiveRules: false,
   esm: false,
   ignores: [],
-  gitignorePath: './.gitignore',
+  gitignore: './.gitignore',
   import: {},
   jest: isPackageExists('jest'),
   next: isPackageExists('next'),
@@ -72,7 +72,7 @@ export function defineConfig(initOptions = {}, ...extend) {
     disableExpensiveRules,
     esm: enableEsm,
     ignores: enableIgnores,
-    gitignorePath,
+    gitignore,
     import: enableImport,
     jest: enableJest,
     next: enableNext,

src/modules/ignore.mjs

@@ -1,17 +1,26 @@
-import { includeIgnoreFile } from '@eslint/compat';
 import { globalIgnores } from 'eslint/config';
-import path from 'node:path';
 
+import { getGitignorePatterns } from '../utils/getGitignorePatterns.mjs';
 import { ignoreGlobs } from '../utils/globs.mjs';
 
 /**
  * @param { import('..').Options } options
  * @return { import('eslint').Linter.Config }
  */
 function ignores(options = {}) {
-  const gitignorePath = path.resolve(process.cwd(), options.gitignorePath);
-  const gitignore = includeIgnoreFile(gitignorePath);
-  return globalIgnores([...gitignore.ignores, ...ignoreGlobs, ...(options.ignores ?? [])], 'ignores');
+  const ignorePatterns = [...ignoreGlobs, ...(options.ignores ?? [])];
+
+  const shouldUseGitignore = options.gitignore && options.gitignore.length > 0;
+  if (shouldUseGitignore) {
+    const gitignorePatterns = getGitignorePatterns(options.gitignore);
+    if (gitignorePatterns.length > 0) {
+      ignorePatterns.push(...gitignorePatterns);
+    }
+  }
+
+  const uniqueIgnorePatterns = [...new Set(ignorePatterns)];
+
+  return globalIgnores(uniqueIgnorePatterns, 'ignores');
 }
 
 export default ignores;

src/utils/getGitignorePatterns.mjs

@@ -0,0 +1,35 @@
+/* eslint 'no-console': ['warn', { allow: ['warn'] }] */
+
+import { includeIgnoreFile } from '@eslint/compat';
+import fs from 'node:fs';
+import path from 'node:path';
+
+const warningMessage = '\u001B[38;2;229;229;14mWarning:\u001B[0m';
+const fallbackMessage =
+  'Falling back to default ignore patterns. You can suppress this warning by setting \u001B[48;5;234m`gitignore: false`\u001B[0m in the config.';
+
+/**
+ * @param {string} gitignorePath relative path to the .gitignore file
+ * @returns {string[]}
+ */
+export function getGitignorePatterns(gitignorePath) {
+  const gitignoreAbsolutePath = path.resolve(process.cwd(), gitignorePath);
+  const gitignoreExists = fs.existsSync(gitignoreAbsolutePath); // eslint-disable-line n/no-sync
+  const gitignorePatterns = [];
+
+  if (!gitignoreExists) {
+    console.warn(warningMessage, `No .gitignore file found at "${gitignoreAbsolutePath}".`, fallbackMessage);
+
+    return gitignorePatterns;
+  }
+
+  const ignorePatterns = includeIgnoreFile(gitignoreAbsolutePath).ignores ?? [];
+
+  if (ignorePatterns.length > 0) {
+    gitignorePatterns.push(...ignorePatterns);
+  } else {
+    console.warn(warningMessage, `No patterns found in .gitignore file at "${gitignoreAbsolutePath}".`, fallbackMessage);
+  }
+
+  return gitignorePatterns;
+}