One config to rule them all (#175)

Fixes #173. Fixes #174.

Author: lydell

.eslintrc.base.js

@@ -3,7 +3,7 @@
 // This file is only used in `./.eslintrc.js` and in the tests – it’s not part
 // of the eslint-config-prettier npm package.
 
-const fs = require("fs");
+const config = require(".");
 
 module.exports = {
   extends: [
@@ -15,13 +15,12 @@ module.exports = {
   ],
   plugins: [
     "prettier",
-    ...fs
-      .readdirSync(__dirname)
-      .filter(
-        (file) =>
-          !file.startsWith(".") && file.endsWith(".js") && file !== "index.js"
-      )
-      .map((ruleFileName) => ruleFileName.replace(/\.js$/, "")),
+    ...new Set(
+      Object.keys(config.rules)
+        .map((ruleName) => ruleName.split("/"))
+        .filter((parts) => parts.length > 1)
+        .map((parts) => parts[0])
+    ),
   ],
   parserOptions: {
     parser: "babel-eslint",
@@ -38,10 +37,10 @@ module.exports = {
     node: true,
   },
   rules: {
-    indent: "off",
+    "indent": "off",
     "linebreak-style": "off",
     "no-dupe-keys": "error",
-    strict: "error",
+    "strict": "error",
     "prefer-spread": "off",
     "require-jsdoc": "off",
     "prettier/prettier": "error",

.eslintrc.js

@@ -6,16 +6,8 @@
 // as an “eat your own dogfood” test. That feels like a good test, but
 // complicates things a little sometimes.
 
-const fs = require("fs");
-
 module.exports = {
-  extends: [
-    "./.eslintrc.base.js",
-    ...fs
-      .readdirSync(__dirname)
-      .filter((file) => !file.startsWith(".") && file.endsWith(".js"))
-      .map((ruleFileName) => `./${ruleFileName}`),
-  ],
+  extends: ["./.eslintrc.base.js", "./index.js", "./prettier.js"],
   rules: {
     "prettier/prettier": "off",
   },
@@ -32,7 +24,7 @@ module.exports = {
               "The comma operator is confusing and a common mistake. Don’t use it!",
           },
         ],
-        quotes: [
+        "quotes": [
           "error",
           "double",
           { avoidEscape: true, allowTemplateLiterals: false },

.prettierrc.json

@@ -1,3 +1,4 @@
 {
-  "proseWrap": "never"
+  "proseWrap": "never",
+  "quoteProps": "consistent"
 }

@typescript-eslint.js

@@ -57,7 +57,7 @@ Then, add eslint-config-prettier to the "extends" array in your `.eslintrc.*` fi
 }
 ```
 
-A few ESLint plugins are supported as well:
+That’s it! Extending `"prettier"` turns off a bunch of core ESLint rules, as well as a few rules from these plugins:
 
 - [@typescript-eslint/eslint-plugin]
 - [eslint-plugin-babel]
@@ -68,40 +68,7 @@ A few ESLint plugins are supported as well:
 - [eslint-plugin-unicorn]
 - [eslint-plugin-vue]
 
-Add extra exclusions for the plugins you use like so:
-
-<!-- prettier-ignore -->
-```json
-{
-  "extends": [
-    "some-other-config-you-use",
-    "prettier",
-    "prettier/@typescript-eslint",
-    "prettier/babel",
-    "prettier/flowtype",
-    "prettier/prettier",
-    "prettier/react",
-    "prettier/standard",
-    "prettier/unicorn",
-    "prettier/vue"
-  ]
-}
-```
-
-If you extend a config which uses a plugin, it is recommended to add `"prettier/that-plugin"` (if available). For example, [eslint-config-airbnb] enables [eslint-plugin-react] rules, so `"prettier/react"` is needed:
-
-<!-- prettier-ignore -->
-```json
-{
-  "extends": [
-    "airbnb",
-    "prettier",
-    "prettier/react"
-  ]
-}
-```
-
-If you’re unsure which plugins are used, you can usually find them in your `package.json`.
+> Note: You might find guides on the Internet saying you should also extend stuff like `"prettier/react"`. Since version 8.0.0 of eslint-config-prettier, all you need to extend is `"prettier"`! That includes all plugins.
 
 ### Excluding deprecated rules
 
@@ -163,14 +130,16 @@ For maximum ease of use, the special rules are disabled by default (provided tha
 
 **These rules might cause problems if using [eslint-plugin-prettier] and `--fix`.**
 
-See [`arrow-body-style` and `prefer-arrow-callback` issue][eslint-plugin-prettier-autofix-issue] for details.
+See the [`arrow-body-style` and `prefer-arrow-callback` issue][eslint-plugin-prettier-autofix-issue] for details.
 
 There are a couple of ways to turn these rules off:
 
 - Put `"prettier/prettier"` in your `"extends"`. (Yes, there’s both a _rule_ called `"prettier/prettier"` and a _config_ called `"prettier/prettier"`.)
 - Use [eslint-plugin-prettier’s recommended config][eslint-plugin-prettier-recommended], which also turns off these two rules.
 - Remove them from your config or turn them off manually.
 
+It doesn’t matter which approach you use – they’re all the same.
+
 Note: The CLI tool only reports these as problematic if the `"prettier/prettier"` _rule_ is enabled for the same file.
 
 These rules are safe to use if you don’t use [eslint-plugin-prettier]. In other words, if you run `eslint --fix` and `prettier --write` as separate steps.
@@ -698,17 +667,11 @@ Have new rules been added since those versions? Have we missed any rules? Is the
 
 If you’d like to add support for eslint-plugin-foobar, this is how you’d go about it:
 
-First, create `foobar.js`:
+First, add rules to `index.js`:
 
 <!-- prettier-ignore -->
 ```js
-"use strict";
-
-module.exports = {
-  rules: {
-    "foobar/some-rule": "off"
-  }
-};
+"foobar/some-rule": "off"
 ```
 
 Then, create `test-lint/foobar.js`:
@@ -729,7 +692,7 @@ Finally, you need to mention the plugin in several places:
 
 - Add eslint-plugin-foobar to the "devDependencies" field in `package.json`.
 - Make sure that at least one rule from eslint-plugin-foobar gets used in `.eslintrc.base.js`.
-- Add it to the list of supported plugins and to the Contributing section in `README.md`.
+- Add it to the lists of supported plugins and in this `README.md`.
 
 When you’re done, run `npm test` to verify that you got it all right. It runs several other npm scripts:
 
@@ -751,7 +714,6 @@ When you’re done, run `npm test` to verify that you got it all right. It runs
 [arrow-body-style]: https://eslint.org/docs/rules/arrow-body-style
 [babel/quotes]: https://github.com/babel/eslint-plugin-babel#rules
 [curly]: https://eslint.org/docs/rules/curly
-[eslint-config-airbnb]: https://www.npmjs.com/package/eslint-config-airbnb
 [eslint-plugin-babel]: https://github.com/babel/eslint-plugin-babel
 [eslint-plugin-flowtype]: https://github.com/gajus/eslint-plugin-flowtype
 [eslint-plugin-prettier-autofix-issue]: https://github.com/prettier/eslint-plugin-prettier#arrow-body-style-and-prefer-arrow-callback-issue

README.md

@@ -2,9 +2,9 @@
 
 "use strict";
 
-const fs = require("fs");
-const path = require("path");
 const validators = require("./validators");
+const config = require("..");
+const prettier = require("../prettier");
 
 // Require locally installed eslint, for `npx eslint-config-prettier` support
 // with no local eslint-config-prettier installation.
@@ -15,6 +15,9 @@ const { ESLint } = require(require.resolve("eslint", {
 const SPECIAL_RULES_URL =
   "https://github.com/prettier/eslint-config-prettier#special-rules";
 
+const PRETTIER_RULES_URL =
+  "https://github.com/prettier/eslint-config-prettier#arrow-body-style-and-prefer-arrow-callback";
+
 if (module === require.main) {
   const args = process.argv.slice(2);
 
@@ -28,8 +31,8 @@ if (module === require.main) {
   Promise.all(args.map((file) => eslint.calculateConfigForFile(file)))
     .then((configs) => {
       const rules = [].concat(
-        ...configs.map((config, index) =>
-          Object.entries(config.rules).map((entry) => [...entry, args[index]])
+        ...configs.map(({ rules }, index) =>
+          Object.entries(rules).map((entry) => [...entry, args[index]])
         )
       );
       const result = processRules(rules);
@@ -68,24 +71,13 @@ https://github.com/prettier/eslint-config-prettier#cli-helper-tool
 }
 
 function processRules(configRules) {
-  // This used to look at "files" in package.json, but that is not reliable due
-  // to an npm bug. See:
-  // https://github.com/prettier/eslint-config-prettier/issues/57
-  const allRules = Object.assign(
-    Object.create(null),
-    ...fs
-      .readdirSync(path.join(__dirname, ".."))
-      .filter((name) => !name.startsWith(".") && name.endsWith(".js"))
-      .map((ruleFileName) => require(`../${ruleFileName}`).rules)
-  );
-
-  const regularRules = filterRules(allRules, (_, value) => value === "off");
+  const regularRules = filterRules(config.rules, (_, value) => value === "off");
   const optionsRules = filterRules(
-    allRules,
+    config.rules,
     (ruleName, value) => value === 0 && ruleName in validators
   );
   const specialRules = filterRules(
-    allRules,
+    config.rules,
     (ruleName, value) => value === 0 && !(ruleName in validators)
   );
 
@@ -99,7 +91,7 @@ function processRules(configRules) {
     .filter(Boolean);
 
   const flaggedRules = enabledRules.filter(
-    ({ ruleName }) => ruleName in allRules
+    ({ ruleName }) => ruleName in config.rules
   );
 
   const regularFlaggedRuleNames = filterRuleNames(
@@ -109,37 +101,21 @@ function processRules(configRules) {
   const optionsFlaggedRuleNames = filterRuleNames(
     flaggedRules,
     ({ ruleName, ...rule }) =>
-      ruleName in optionsRules && !validators[ruleName](rule, enabledRules)
+      ruleName in optionsRules && !validators[ruleName](rule)
   );
   const specialFlaggedRuleNames = filterRuleNames(
     flaggedRules,
     ({ ruleName }) => ruleName in specialRules
   );
-
-  if (
-    regularFlaggedRuleNames.length === 0 &&
-    optionsFlaggedRuleNames.length === 0
-  ) {
-    const baseMessage =
-      "No rules that are unnecessary or conflict with Prettier were found.";
-
-    const message =
-      specialFlaggedRuleNames.length === 0
-        ? baseMessage
-        : [
-            baseMessage,
-            "",
-            "However, the following rules are enabled but cannot be automatically checked. See:",
-            SPECIAL_RULES_URL,
-            "",
-            printRuleNames(specialFlaggedRuleNames),
-          ].join("\n");
-
-    return {
-      stdout: message,
-      code: 0,
-    };
-  }
+  const prettierFlaggedRuleNames = filterRuleNames(
+    enabledRules,
+    ({ ruleName, source }) =>
+      ruleName in prettier.rules &&
+      enabledRules.some(
+        (rule) =>
+          rule.ruleName === "prettier/prettier" && rule.source === source
+      )
+  );
 
   const regularMessage = [
     "The following rules are unnecessary or might conflict with Prettier:",
@@ -161,10 +137,41 @@ function processRules(configRules) {
     printRuleNames(specialFlaggedRuleNames),
   ].join("\n");
 
+  const prettierMessage = [
+    "The following rules can cause issues when using eslint-plugin-prettier at the same time.",
+    "Only enable them if you know what you are doing! See:",
+    PRETTIER_RULES_URL,
+    "",
+    printRuleNames(prettierFlaggedRuleNames),
+  ].join("\n");
+
+  if (
+    regularFlaggedRuleNames.length === 0 &&
+    optionsFlaggedRuleNames.length === 0
+  ) {
+    const message =
+      specialFlaggedRuleNames.length === 0 &&
+      prettierFlaggedRuleNames.length === 0
+        ? "No rules that are unnecessary or conflict with Prettier were found."
+        : [
+            specialFlaggedRuleNames.length === 0 ? null : specialMessage,
+            prettierFlaggedRuleNames.length === 0 ? null : prettierMessage,
+            "Other than that, no rules that are unnecessary or conflict with Prettier were found.",
+          ]
+            .filter(Boolean)
+            .join("\n\n");
+
+    return {
+      stdout: message,
+      code: 0,
+    };
+  }
+
   const message = [
     regularFlaggedRuleNames.length === 0 ? null : regularMessage,
     optionsFlaggedRuleNames.length === 0 ? null : optionsMessage,
     specialFlaggedRuleNames.length === 0 ? null : specialMessage,
+    prettierFlaggedRuleNames.length === 0 ? null : prettierMessage,
   ]
     .filter(Boolean)
     .join("\n\n");