Fix browserslist support, added options to disable browserlist feature

README.md

@@ -39,7 +39,7 @@ We use [browserslist](https://github.com/browserslist/browserslist) to resolve b
 
 ## 4. Customizing rules
 
-By default, the plugin will report on all lookahead and lookbehind regexp as well as their negative counterparts. To enable only individual rules like erroring only on lookbehind expressions, you can pass a list of rules that you wish to enable as options in your eslint. **Note that once a single rule is passed as a configuration option, all of the other rules are disabled by default and you are in full control.**
+By default, the plugin will report on all lookahead and lookbehind regexp as well as their negative counterparts(if they are not supported with above browserslist target settings). To enable only individual rules like erroring only on lookbehind expressions, you can pass a list of rules that you wish to enable as options in your eslint. **Note that once a single rule is passed as a configuration option, all of the other rules are disabled by default and you are in full control.**
 
 ```js
 rules: {
@@ -53,14 +53,16 @@ rules: {
 }
 ```
 
-As an example, passing both no-lookbehind and no-negative-lookbehind as options will cause the plugin to error on all lookbehind and negative lookbehind expressions, but it will not cause it to report errors on lookahead or negative lookahead expressions.
+## 5. Disable Browserslist Support
+
+By default, the plugin will use yours project's browserslist settings to find availability of lookahead/lookbehind and their negative counterparts. However, if you want to disable this feature to report all usages(still controlled by above rules settings) as errors, you can pass an additional object options.
 
 ```js
 rules: {
    'no-lookahead-lookbehind-regexp/no-lookahead-lookbehind-regexp': [
       'error',
-      'no-lookbehind',
-      'no-negative-lookbehind',
+      'no-lookahead',
+      { browserslist: false },
    ],
 }
 ```

benchmark/benchmark.ts

@@ -21,7 +21,7 @@ const config = {
 
 const eslint = new ESLint(config);
 const benchmark = new Benchmark(
-  "ESLint self benchmark w/o browserlist",
+  "ESLint self benchmark w/o browserslist",
   (deferred: { resolve: Function }) => {
     eslint
       .lintFiles("src/**/*.ts")
@@ -63,7 +63,7 @@ eslint
   });
 
 const browserlistBenchmark = new Benchmark(
-  "ESLint self benchmark with browserlist",
+  "ESLint self benchmark with browserslist",
   (deferred: { resolve: Function; reject: Function }) => {
     eslint
       .lintFiles("src/**/*.ts")

package.json

@@ -1,6 +1,6 @@
 {
   "name": "eslint-plugin-no-lookahead-lookbehind-regexp",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "main": "lib/index.js",
   "types": "lib/index.d.ts",
   "repository": "git@github.com:JonasBa/eslint-plugin-no-lookahead-lookbehind-regexp.git",
@@ -12,7 +12,6 @@
   },
   "scripts": {
     "benchmark": "ts-node test/benchmark.ts",
-    "prepare": "yarn test && yarn build",
     "build": "rm -rf ./lib && yarn tsc",
     "tsc": "tsc",
     "test": "jest",

src/helpers/analyzeRegExpForLookaheadAndLookbehind.test.ts

@@ -10,9 +10,10 @@ describe("analyzeRegExpForLookaheadAndLookbehind", () => {
   it("does not return false positives for an escaped sequence", () => {
     for (const group of groups) {
       expect(
-        analyzeRegExpForLookaheadAndLookbehind(`\\(${group}`, {
-          rules: getExpressionsToCheckFromConfiguration([]),
-        }).length
+        analyzeRegExpForLookaheadAndLookbehind(
+          `\\(${group}`,
+          getExpressionsToCheckFromConfiguration([]).rules
+        ).length
       ).toBe(0);
     }
   });
@@ -24,9 +25,10 @@ describe("analyzeRegExpForLookaheadAndLookbehind", () => {
     ["negative lookbehind", 0, "(?<!)"],
   ])(`Single match %s - at %i`, (type, position, expression) => {
     expect(
-      analyzeRegExpForLookaheadAndLookbehind(expression, {
-        rules: getExpressionsToCheckFromConfiguration([]),
-      })[0]
+      analyzeRegExpForLookaheadAndLookbehind(
+        expression,
+        getExpressionsToCheckFromConfiguration([]).rules
+      )[0]
     ).toEqual({
       type: type.replace("negative ", ""),
       position: position,
@@ -41,9 +43,10 @@ describe("analyzeRegExpForLookaheadAndLookbehind", () => {
     ["negative lookbehind", 0, 8, "(?<!t).*(?<!t)"],
   ])(`Multiple match %s - at %i and %i`, (type, first, second, expression) => {
     expect(
-      analyzeRegExpForLookaheadAndLookbehind(expression, {
-        rules: getExpressionsToCheckFromConfiguration([]),
-      })
+      analyzeRegExpForLookaheadAndLookbehind(
+        expression,
+        getExpressionsToCheckFromConfiguration([]).rules
+      )
     ).toEqual([
       {
         type: type.replace("negative ", ""),
@@ -76,15 +79,14 @@ describe("analyzeRegExpForLookaheadAndLookbehind", () => {
     for (const expression in expressions) {
       if (rule === expression) {
         expect(
-          analyzeRegExpForLookaheadAndLookbehind(expressions[expression], {
-            rules: { [expression]: 0 },
-          })
+          analyzeRegExpForLookaheadAndLookbehind(expressions[expression], { [expression]: 0 })
         ).toEqual([]);
       } else {
         expect(
-          analyzeRegExpForLookaheadAndLookbehind(expressions[expression], {
-            rules: getExpressionsToCheckFromConfiguration([]),
-          })
+          analyzeRegExpForLookaheadAndLookbehind(
+            expressions[expression],
+            getExpressionsToCheckFromConfiguration([]).rules
+          )
         ).toEqual([
           {
             position: 0,

src/helpers/analyzeRegExpForLookaheadAndLookbehind.ts

@@ -6,6 +6,7 @@ export type CheckableExpression =
 
 export type AnalyzeOptions = {
   rules: Partial<{ [key in `no-${CheckableExpression}`]: 0 | 1 }>;
+  conf: Partial<{ browserslist: boolean }>;
 };
 
 type UnsupportedExpression = {
@@ -16,7 +17,7 @@ type UnsupportedExpression = {
 
 function analyzeRegExpForLookaheadAndLookbehind(
   input: string,
-  options: AnalyzeOptions
+  rules: AnalyzeOptions["rules"]
 ): UnsupportedExpression[] {
   // Lookahead and lookbehind require min 5 characters to be useful, however
   // an expression like /(?=)/ which uses only 4, although not useful, can still crash an application
@@ -47,7 +48,7 @@ function analyzeRegExpForLookaheadAndLookbehind(
 
           // Lookahead
           if (peek() === "=") {
-            if (options.rules["no-lookahead"]) {
+            if (rules["no-lookahead"]) {
               matchedExpressions.push({
                 type: "lookahead",
                 position: start,
@@ -58,7 +59,7 @@ function analyzeRegExpForLookaheadAndLookbehind(
           }
           // Negative lookahead
           if (peek() === "!") {
-            if (options.rules["no-negative-lookahead"]) {
+            if (rules["no-negative-lookahead"]) {
               matchedExpressions.push({
                 type: "lookahead",
                 negative: 1,
@@ -72,7 +73,7 @@ function analyzeRegExpForLookaheadAndLookbehind(
           // Lookbehind
           if (peek() === "<") {
             if (input.charAt(current + 2) === "=") {
-              if (options.rules["no-lookbehind"]) {
+              if (rules["no-lookbehind"]) {
                 matchedExpressions.push({
                   type: "lookbehind",
                   position: start,
@@ -84,7 +85,7 @@ function analyzeRegExpForLookaheadAndLookbehind(
             }
             // Negative Lookbehind
             if (input.charAt(current + 2) === "!") {
-              if (options.rules["no-negative-lookbehind"]) {
+              if (rules["no-negative-lookbehind"]) {
                 matchedExpressions.push({
                   type: "lookbehind",
                   negative: 1,

src/helpers/caniuse.ts

@@ -14,6 +14,8 @@ export function collectBrowserTargets(
   configPath: string,
   config?: { production: string[]; development: string[] } | Array<string> | string
 ): { targets: BrowserTarget[]; hasConfig: boolean } {
+  const browserslistConfig = browserslist.findConfig(configPath);
+  const hasConfig = (browserslistConfig && browserslistConfig.defaults.length > 0) || false;
   const targets = new Set<string>();
 
   function addTarget(target: string): void {
@@ -35,35 +37,35 @@ export function collectBrowserTargets(
     }).forEach(addTarget);
   }
 
-  // If user had eslint config and also has browserlist config, then merge the two
-  if (targets.size > 0 && browserslist.findConfig(configPath)) {
+  // If user had eslint config and also has browserslist config, then merge the two
+  if (targets.size > 0 && hasConfig) {
     browserslist(undefined, { path: configPath }).forEach(addTarget);
-    return { targets: Array.from(targets).map(transformTarget), hasConfig: true };
+    return { targets: Array.from(targets).map(transformTarget), hasConfig };
   }
 
   // If they only use an eslint config, then return what we have
-  if (targets.size > 0 && !browserslist.findConfig(configPath)) {
-    return { targets: Array.from(targets).map(transformTarget), hasConfig: true };
+  if (targets.size > 0 && !hasConfig) {
+    return { targets: Array.from(targets).map(transformTarget), hasConfig };
   }
 
   // ** Warning
-  // If they dont use a browserlist config, then return an empty targets array and disable the use of the regexp lookahead and lookbehind entirely.
-  if (!browserslist.findConfig(configPath)) {
-    return { targets: [], hasConfig: false };
+  // If they don't use a browserslist config, then return an empty targets array and disable the use of the regexp lookahead and lookbehind entirely.
+  if (!hasConfig) {
+    return { targets: [], hasConfig };
   }
 
   browserslist(undefined, { path: configPath }).forEach(addTarget);
   // If we couldnt find anything, return empty targets and indicate that no config was found
-  return { targets: Array.from(targets).map(transformTarget), hasConfig: false };
+  return { targets: Array.from(targets).map(transformTarget), hasConfig };
 }
 
 // Returns a list of browser targets that do not support a feature.
 // In case feature stats are not found in the database, we will assume that the feature is supported,
 // this can result in false positives when querying for versions that may not have been released yet (typo or user mistake)
 // Since the equivalent can happen in case of specifying some super old version, the proper way to possibly handle
 // this would be to throw an error, but since I dont know how often that happens or if it may cause false positives later on
-// if caniuse db changes... I'm leaning towards throwing an error here, but it's not the plugin's responsability to validate browserlist config - opinions are welcome.
-// TODO: check if browserlist throws an error lower in the stack if config is invalid, this would likely be the best solution
+// if caniuse db changes... I'm leaning towards throwing an error here, but it's not the plugin's responsability to validate browserslist config - opinions are welcome.
+// TODO: check if browserslist throws an error lower in the stack if config is invalid, this would likely be the best solution
 export function collectUnsupportedTargets(id: string, targets: BrowserTarget[]): BrowserTarget[] {
   const data = lite.feature(lite.features[id]);
 
@@ -114,8 +116,7 @@ export function resolveCaniUseBrowserTarget(target: string): string {
 
 export function formatLinterMessage(
   violators: ReturnType<typeof analyzeRegExpForLookaheadAndLookbehind>,
-  targets: ReturnType<typeof collectUnsupportedTargets>
-): string {
+  targets: ReturnType<typeof collectUnsupportedTargets>): string {
   // If browser has no targets and we still want to report an error, it means that the feature is banned from use.
   if (!targets.length) {
     if (violators.length === 1) {

src/helpers/createReport.ts

@@ -1,14 +1,14 @@
 import * as ESTree from "estree";
 import { Rule } from "eslint";
 
-import { analyzeRegExpForLookaheadAndLookbehind } from "./../helpers/analyzeRegExpForLookAheadAndLookbehind";
-import { collectUnsupportedTargets, formatLinterMessage } from "./../helpers/caniuse";
+import { analyzeRegExpForLookaheadAndLookbehind } from "../helpers/analyzeRegExpForLookaheadAndLookbehind";
+import { collectUnsupportedTargets, formatLinterMessage } from "../helpers/caniuse";
 
 export function createContextReport(
   node: ESTree.Literal & Rule.NodeParentExtension,
   context: Rule.RuleContext,
   violators: ReturnType<typeof analyzeRegExpForLookaheadAndLookbehind>,
-  targets: ReturnType<typeof collectUnsupportedTargets>
+  targets: ReturnType<typeof collectUnsupportedTargets>,
 ): void {
   context.report({
     node: node,

src/rules/noLookAheadLookBehindRegExp.test.ts

@@ -1,7 +1,7 @@
 import { RuleTester } from "eslint";
 import { noLookaheadLookbehindRegexp } from "./noLookaheadLookbehindRegex";
 
-// Rule tester for when no browserlist is passed, so lookahead and lookbehind should not be allowed
+// Rule tester for when no browserslist is passed, so lookahead and lookbehind should not be allowed
 const tester = new RuleTester({
   parser: require.resolve("@typescript-eslint/parser"),
   parserOptions: {

src/rules/noLookaheadLookbehindRegex.ts

@@ -5,9 +5,9 @@ import {
   analyzeRegExpForLookaheadAndLookbehind,
   AnalyzeOptions,
   CheckableExpression,
-} from "./../helpers/analyzeRegExpForLookAheadAndLookbehind";
-import { collectBrowserTargets, collectUnsupportedTargets } from "./../helpers/caniuse";
-import { isStringLiteralRegExp, isRegExpLiteral } from "./../helpers/ast";
+} from "../helpers/analyzeRegExpForLookaheadAndLookbehind";
+import { collectBrowserTargets, collectUnsupportedTargets } from "../helpers/caniuse";
+import { isStringLiteralRegExp, isRegExpLiteral } from "../helpers/ast";
 import { createContextReport } from "../helpers/createReport";
 
 export const DEFAULT_OPTIONS: AnalyzeOptions["rules"] = {
@@ -17,21 +17,35 @@ export const DEFAULT_OPTIONS: AnalyzeOptions["rules"] = {
   "no-negative-lookbehind": 1,
 };
 
+export const DEFAULT_CONF: AnalyzeOptions["conf"] = {
+  browserslist: true,
+};
+
+function isPlainObject(obj: any) {
+  return Object.prototype.toString.call(obj) === "[object Object]";
+}
+
 export const getExpressionsToCheckFromConfiguration = (
   options: Rule.RuleContext["options"]
-): AnalyzeOptions["rules"] => {
-  if (!options.length) return DEFAULT_OPTIONS;
+): { rules: AnalyzeOptions["rules"]; conf: AnalyzeOptions["conf"] } => {
+  if (!options.length) return { rules: DEFAULT_OPTIONS, conf: DEFAULT_CONF };
+  let rules: CheckableExpression[] = options;
+  let conf: AnalyzeOptions["conf"] = {};
+  if (isPlainObject(options[options.length - 1])) {
+    rules = options.slice(0, -1);
+    conf = options[options.length - 1];
+  }
 
-  const validOptions: CheckableExpression[] = options.filter((option: unknown) => {
+  const validOptions: CheckableExpression[] = rules.filter((option: unknown) => {
     if (typeof option !== "string") return false;
     return DEFAULT_OPTIONS[option as keyof typeof DEFAULT_OPTIONS];
   });
 
   if (!validOptions.length) {
-    return DEFAULT_OPTIONS;
+    return { rules: DEFAULT_OPTIONS, conf };
   }
 
-  return validOptions.reduce<AnalyzeOptions["rules"]>(
+  const expressions = validOptions.reduce<AnalyzeOptions["rules"]>(
     (acc: AnalyzeOptions["rules"], opt) => {
       acc[opt as keyof typeof DEFAULT_OPTIONS] = 1;
       return acc;
@@ -43,12 +57,17 @@ export const getExpressionsToCheckFromConfiguration = (
       "no-negative-lookbehind": 0,
     }
   );
+  return {
+    rules: expressions,
+    conf,
+  };
 };
 
 const noLookaheadLookbehindRegexp: Rule.RuleModule = {
   meta: {
     docs: {
-      description: "disallow the use of lookahead and lookbehind regexes if unsupported by browser",
+      description:
+        "disallow the use of lookahead and lookbehind regular expressions if unsupported by browser",
       category: "Compatibility",
       recommended: true,
     },
@@ -57,27 +76,33 @@ const noLookaheadLookbehindRegexp: Rule.RuleModule = {
   create(context: Rule.RuleContext) {
     const browsers = context.settings.browsers || context.settings.targets;
     const { targets, hasConfig } = collectBrowserTargets(context.getFilename(), browsers);
+    // Lookahead assertions are part of JavaScript's original regular expression support and are thus supported in all browsers.
     const unsupportedTargets = collectUnsupportedTargets("js-regexp-lookbehind", targets);
-    const rules = getExpressionsToCheckFromConfiguration(context.options);
+    const {
+      rules,
+      conf: { browserslist },
+    } = getExpressionsToCheckFromConfiguration(context.options);
 
-    // If there are no unsupported targets resolved from the browserlist config, then we can skip this rule
+    // If there are no unsupported targets resolved from the browserslist config, then we can skip this rule
     if (!unsupportedTargets.length && hasConfig) return {};
 
     return {
       Literal(node: ESTree.Literal & Rule.NodeParentExtension): void {
+        let input: string = "";
         if (isStringLiteralRegExp(node) && typeof node.raw === "string") {
-          const unsupportedGroups = analyzeRegExpForLookaheadAndLookbehind(
-            node.raw,
-            { rules } // For string literals, we need to pass the raw value which includes escape characters.
-          );
-          if (unsupportedGroups.length > 0) {
+          // For string literals, we need to pass the raw value which includes escape characters.
+          input = node.raw;
+        } else if (isRegExpLiteral(node)) {
+          input = node.regex.pattern;
+        }
+        if (input) {
+          const unsupportedGroups = analyzeRegExpForLookaheadAndLookbehind(input, rules);
+          if (unsupportedGroups.length === 0) return;
+          if (!browserslist) {
             createContextReport(node, context, unsupportedGroups, unsupportedTargets);
+            return;
           }
-        } else if (isRegExpLiteral(node)) {
-          const unsupportedGroups = analyzeRegExpForLookaheadAndLookbehind(node.regex.pattern, {
-            rules,
-          });
-          if (unsupportedGroups.length > 0) {
+          if (unsupportedGroups.some((group) => group.type === "lookbehind")) {
             createContextReport(node, context, unsupportedGroups, unsupportedTargets);
           }
         }