Examples

// Flat config (basic)
// Goal: enforce the JS Baseline at "widely".
// Web APIs/JS builtins detection is off by default here.
// For broader detection, use the recommended preset or explicitly enable
// includeWebApis/includeJsBuiltins.

import baselineJs, { BASELINE } from "eslint-plugin-baseline-js";

export default [
  {
    files: ["**/*.{js,ts,mjs,cjs,jsx,tsx}"],
    plugins: { "baseline-js": baselineJs },
    rules: {
      // Baseline policy: "widely" = allow only widely available features
      "baseline-js/use-baseline": ["error", { available: BASELINE.WIDELY }],
      // Example: also detect Web APIs/JS builtins (opt-in):
      // "baseline-js/use-baseline": ["error", {
      //   available: BASELINE.WIDELY,
      //   includeWebApis: { preset: "auto" },
      //   includeJsBuiltins: { preset: "auto" },
      // }],
    },
  },
];

// Flat config (recommended)
// Enables Web APIs and JS builtins detection by default (preset: "auto").
// Good default when you want broad Baseline coverage with minimal config.

import baselineJs, { BASELINE } from "eslint-plugin-baseline-js";

export default [
  // Register the plugin once so its rules are available below
  { plugins: { "baseline-js": baselineJs } },

  // Baseline: defaults to "widely"; override via function argument if needed.
  // Level defaults to "error"; switch to "warn" by passing level.
  baselineJs.configs.recommended({ available: BASELINE.WIDELY, level: "warn" }),
];

// Flat config (TypeScript recommended)
// Uses type-required detection (preset: "type-aware").
// Enables precise instance-member checks (e.g., Iterator helpers, TypedArray methods).
// Requires @typescript-eslint/parser and a valid tsconfig.

import tsParser from "@typescript-eslint/parser"; // Install separately
import baselineJs, { BASELINE } from "eslint-plugin-baseline-js";

export default [
  // Register the plugin so its rules are available across the config
  { plugins: { "baseline-js": baselineJs } },

  // TypeScript parsing setup
  {
    files: ["**/*.{ts,tsx}"],
    languageOptions: {
      parser: tsParser,
      parserOptions: {
        // Simplest: auto-detect the nearest tsconfig.json
        project: true,
        // Or explicitly point to one or more configs (monorepo):
        // project: ["./tsconfig.json"],
      },
    },
  },

  // Baseline + type-aware detection
  baselineJs.configs["recommended-ts"]({ available: BASELINE.WIDELY, level: "error" }),
];

// Flat config (year-based)
// Set a Baseline year (e.g., allow features that became Baseline by 2020).
// Includes examples of ignore knobs and narrowing detection to specific features.

import baselineJs from "eslint-plugin-baseline-js";

export default [
  {
    files: ["**/*.{js,ts,mjs,cjs,jsx,tsx}"],
    plugins: { "baseline-js": baselineJs },
    rules: {
      "baseline-js/use-baseline": [
        "error",
        {
          available: 2020, // Allow only features Baseline'd in or before 2020
          // Exclude specific features (web-features IDs or /.../ regex)
          ignoreFeatures: ["nullish-coalescing", "/^optional-/"],
          // Suppress by ESTree node.type (supports /.../ regex)
          ignoreNodeTypes: ["WithStatement", "/Expression$/"],
          // Explicitly enable Web APIs/JS builtins detection
          includeWebApis: { preset: "auto" },
          includeJsBuiltins: {
            preset: "auto",
            // Example: narrow to specific featureIds
            // only: ["javascript.array-grouping"],
          },
        },
      ],
    },
  },
];

// Flat config (full) — JS + CSS + HTML Baseline
// Goal: enforce Baseline consistently across JavaScript, CSS, and HTML.
// Notes:
// - JS uses this plugin with the "recommended" preset (Web APIs/JS builtins).
// - CSS uses @eslint/css with its "use-baseline" rule.
// - HTML uses @html-eslint/eslint-plugin with its "use-baseline" rule.

import css from "@eslint/css";
import html from "@html-eslint/eslint-plugin";
import htmlParser from "@html-eslint/parser";
import baselineJs, { BASELINE } from "eslint-plugin-baseline-js";
import globals from "globals";

export default [
  // Shared: browser globals (adjust per project: browser/worker/node)
  {
    languageOptions: {
      globals: globals.browser,
    },
  },

  // JavaScript (JS/TS)
  // Broad coverage with minimal config: Web APIs and JS builtins on preset: "auto".
  { plugins: { "baseline-js": baselineJs } },
  baselineJs.configs.recommended({ available: BASELINE.WIDELY, level: "error" }),

  // CSS
  {
    files: ["**/*.css"],
    plugins: { css },
    language: "css/css",
    rules: {
      // Allow only widely available CSS features
      "css/use-baseline": ["error", { available: BASELINE.WIDELY }],
    },
  },

  // HTML
  {
    files: ["**/*.html"],
    plugins: { "@html-eslint": html },
    languageOptions: { parser: htmlParser },
    rules: {
      // Allow only widely available HTML features
      "@html-eslint/use-baseline": ["error", { available: BASELINE.WIDELY }],
    },
  },
];

// Legacy config (.eslintrc.*) — basic
// Note: The plugin recommends Flat Config, but legacy configs work too.

const { BASELINE } = require('eslint-plugin-baseline-js');

module.exports = {
  // Limit target files via overrides as needed
  plugins: ["baseline-js"],
  rules: {
    // Baseline: "newly" (more permissive than "widely")
    "baseline-js/use-baseline": ["warn", { available: BASELINE.NEWLY }],
  },
};

// Legacy config (.eslintrc.*) — year-based
// Goal: allow only features that became Baseline in or before 2018.

module.exports = {
  plugins: ["baseline-js"],
  rules: {
    "baseline-js/use-baseline": [
      "error",
      {
        available: 2018,
        // Enable Web APIs/JS builtins detection
        includeWebApis: { preset: "auto" },
        includeJsBuiltins: { preset: "auto" },
      },
    ],
  },
};