Merge pull request #257 from eslint-functional/issue/244

Author: RebeccaStevens

docs/rules/functional-parameters.md

@@ -56,6 +56,7 @@ type Options = {
     ignoreIIFE: boolean;
   };
   ignorePattern?: string[] | string;
+  ignorePrefixSelector?: string[] | string;
 }
 ```
 
@@ -136,6 +137,31 @@ See [enforceParameterCount](#enforceparametercount).
 
 If true, this option allows for the use of [IIFEs](https://developer.mozilla.org/en-US/docs/Glossary/IIFE) that do not have any parameters.
 
+### `ignorePrefixSelector`
+
+This allows for ignore functions where one of the given selectors matches the parent node in the AST of the function node.\
+For more information see [ESLint Selectors](https://eslint.org/docs/developer-guide/selectors).
+
+Example:
+
+With the following config:
+
+```json
+{
+  "enforceParameterCount": "exactlyOne",
+  "ignorePrefixSelector": "CallExpression[callee.property.name='reduce']"
+},
+```
+
+The following inline callback won't be flagged:
+
+```js
+const sum = [1, 2, 3].reduce(
+  (carry, current) => current,
+  0
+);
+```
+
 ### `ignorePattern`
 
 Patterns will be matched against function names.

src/common/ignore-options.ts

@@ -108,6 +108,25 @@ export const ignoreInterfaceOptionSchema: JSONSchema4["properties"] = {
   },
 };
 
+/**
+ * The option to ignore prefix selector.
+ */
+export type IgnorePrefixSelectorOption = {
+  readonly ignorePrefixSelector?: ReadonlyArray<string> | string;
+};
+
+/**
+ * The schema for the option to ignore prefix selector.
+ */
+export const ignorePrefixSelectorOptionSchema: JSONSchema4["properties"] = {
+  ignorePrefixSelector: {
+    type: ["string", "array"],
+    items: {
+      type: "string",
+    },
+  },
+};
+
 /**
  * Should the given text be allowed?
  *

src/rules/functional-parameters.ts

@@ -3,14 +3,18 @@ import { deepmerge } from "deepmerge-ts";
 import type { JSONSchema4 } from "json-schema";
 import type { ReadonlyDeep } from "type-fest";
 
-import type { IgnorePatternOption } from "~/common/ignore-options";
+import type {
+  IgnorePatternOption,
+  IgnorePrefixSelectorOption,
+} from "~/common/ignore-options";
 import {
   shouldIgnorePattern,
   ignorePatternOptionSchema,
+  ignorePrefixSelectorOptionSchema,
 } from "~/common/ignore-options";
 import type { ESFunction } from "~/src/util/node-types";
 import type { RuleResult } from "~/util/rule";
-import { createRule } from "~/util/rule";
+import { createRuleUsingFunction } from "~/util/rule";
 import { isIIFE, isPropertyAccess, isPropertyName } from "~/util/tree";
 import { isRestElement } from "~/util/typeguard";
 
@@ -29,6 +33,7 @@ type ParameterCountOptions = "atLeastOne" | "exactlyOne";
  */
 type Options = readonly [
   IgnorePatternOption &
+    IgnorePrefixSelectorOption &
     Readonly<{
       allowRestParameter: boolean;
       allowArgumentsKeyword: boolean;
@@ -48,39 +53,43 @@ type Options = readonly [
 const schema: JSONSchema4 = [
   {
     type: "object",
-    properties: deepmerge(ignorePatternOptionSchema, {
-      allowRestParameter: {
-        type: "boolean",
-      },
-      allowArgumentsKeyword: {
-        type: "boolean",
-      },
-      enforceParameterCount: {
-        oneOf: [
-          {
-            type: "boolean",
-            enum: [false],
-          },
-          {
-            type: "string",
-            enum: ["atLeastOne", "exactlyOne"],
-          },
-          {
-            type: "object",
-            properties: {
-              count: {
-                type: "string",
-                enum: ["atLeastOne", "exactlyOne"],
-              },
-              ignoreIIFE: {
-                type: "boolean",
+    properties: deepmerge(
+      ignorePatternOptionSchema,
+      ignorePrefixSelectorOptionSchema,
+      {
+        allowRestParameter: {
+          type: "boolean",
+        },
+        allowArgumentsKeyword: {
+          type: "boolean",
+        },
+        enforceParameterCount: {
+          oneOf: [
+            {
+              type: "boolean",
+              enum: [false],
+            },
+            {
+              type: "string",
+              enum: ["atLeastOne", "exactlyOne"],
+            },
+            {
+              type: "object",
+              properties: {
+                count: {
+                  type: "string",
+                  enum: ["atLeastOne", "exactlyOne"],
+                },
+                ignoreIIFE: {
+                  type: "boolean",
+                },
               },
+              additionalProperties: false,
             },
-            additionalProperties: false,
-          },
-        ],
-      },
-    }),
+          ],
+        },
+      }
+    ),
     additionalProperties: false,
   },
 ];
@@ -255,14 +264,36 @@ function checkIdentifier(
 }
 
 // Create the rule.
-export const rule = createRule<keyof typeof errorMessages, Options>(
-  name,
-  meta,
-  defaultOptions,
-  {
-    FunctionDeclaration: checkFunction,
-    FunctionExpression: checkFunction,
-    ArrowFunctionExpression: checkFunction,
+export const rule = createRuleUsingFunction<
+  keyof typeof errorMessages,
+  Options
+>(name, meta, defaultOptions, (context, options) => {
+  const [optionsObject] = options;
+  const { ignorePrefixSelector } = optionsObject;
+
+  const baseFunctionSelectors = [
+    "ArrowFunctionExpression",
+    "FunctionDeclaration",
+    "FunctionExpression",
+  ];
+
+  const ignoreSelectors: ReadonlyArray<string> | undefined =
+    ignorePrefixSelector === undefined
+      ? undefined
+      : Array.isArray(ignorePrefixSelector)
+      ? ignorePrefixSelector
+      : [ignorePrefixSelector];
+
+  const fullFunctionSelectors = baseFunctionSelectors.flatMap((baseSelector) =>
+    ignoreSelectors === undefined
+      ? [baseSelector]
+      : `:not(:matches(${ignoreSelectors.join(",")})) > ${baseSelector}`
+  );
+
+  return {
+    ...Object.fromEntries(
+      fullFunctionSelectors.map((selector) => [selector, checkFunction])
+    ),
     Identifier: checkIdentifier,
-  }
-);
+  };
+});

src/util/rule.ts

@@ -89,16 +89,45 @@ export function createRule<
   meta: ESLintUtils.NamedCreateRuleMeta<MessageIds>,
   defaultOptions: Options,
   ruleFunctionsMap: RuleFunctionsMap<any, MessageIds, Options>
-) {
+): Rule.RuleModule {
+  return createRuleUsingFunction(
+    name,
+    meta,
+    defaultOptions,
+    () => ruleFunctionsMap
+  );
+}
+
+/**
+ * Create a rule.
+ */
+export function createRuleUsingFunction<
+  MessageIds extends string,
+  Options extends BaseOptions
+>(
+  name: string,
+  meta: ESLintUtils.NamedCreateRuleMeta<MessageIds>,
+  defaultOptions: Options,
+  createFunction: (
+    context: ReadonlyDeep<TSESLint.RuleContext<MessageIds, Options>>,
+    options: Options
+  ) => RuleFunctionsMap<any, MessageIds, Options>
+): Rule.RuleModule {
   return ESLintUtils.RuleCreator(
     (ruleName) =>
       `https://github.com/eslint-functional/eslint-plugin-functional/blob/v${__VERSION__}/docs/rules/${ruleName}.md`
   )({
     name,
     meta,
     defaultOptions,
-    create: (context, options) =>
-      Object.fromEntries(
+    create: (context, options) => {
+      const ruleFunctionsMap = createFunction(
+        context as unknown as ReadonlyDeep<
+          TSESLint.RuleContext<MessageIds, Options>
+        >,
+        options as unknown as Options
+      );
+      return Object.fromEntries(
         Object.entries(ruleFunctionsMap).map(([nodeSelector, ruleFunction]) => [
           nodeSelector,
           checkNode(
@@ -109,7 +138,8 @@ export function createRule<
             options as unknown as Options
           ),
         ])
-      ),
+      );
+    },
   }) as unknown as Rule.RuleModule;
 }
 

tests/rules/functional-parameters/es3/invalid.ts

@@ -99,6 +99,37 @@ const tests: ReadonlyArray<InvalidTestCase> = [
       },
     ],
   },
+  {
+    code: dedent`
+      [1, 2, 3]
+        .map(
+          function(element, index) {
+            return element + index;
+          }
+        )
+        .reduce(
+          function(carry, current) {
+            return carry + current;
+          },
+          0
+        );
+    `,
+    optionsSet: [[{ enforceParameterCount: "exactlyOne" }]],
+    errors: [
+      {
+        messageId: "paramCountExactlyOne",
+        type: "FunctionExpression",
+        line: 3,
+        column: 5,
+      },
+      {
+        messageId: "paramCountExactlyOne",
+        type: "FunctionExpression",
+        line: 8,
+        column: 5,
+      },
+    ],
+  },
 ];
 
 export default tests;

tests/rules/functional-parameters/es3/valid.ts

@@ -42,6 +42,69 @@ const tests: ReadonlyArray<ValidTestCase> = [
       [{ ignorePattern: "^foo", enforceParameterCount: "exactlyOne" }],
     ],
   },
+  {
+    code: dedent`
+      [1, 2, 3].reduce(
+        function(carry, current) {
+          return carry + current;
+        },
+        0
+      );
+    `,
+    optionsSet: [
+      [
+        {
+          ignorePrefixSelector: "CallExpression[callee.property.name='reduce']",
+          enforceParameterCount: "exactlyOne",
+        },
+      ],
+    ],
+  },
+  {
+    code: dedent`
+      [1, 2, 3].map(
+        function(element, index) {
+          return element + index;
+        },
+        0
+      );
+    `,
+    optionsSet: [
+      [
+        {
+          enforceParameterCount: "exactlyOne",
+          ignorePrefixSelector: "CallExpression[callee.property.name='map']",
+        },
+      ],
+    ],
+  },
+  {
+    code: dedent`
+      [1, 2, 3]
+        .map(
+          function(element, index) {
+            return element + index;
+          }
+        )
+        .reduce(
+          function(carry, current) {
+            return carry + current;
+          },
+          0
+        );
+    `,
+    optionsSet: [
+      [
+        {
+          enforceParameterCount: "exactlyOne",
+          ignorePrefixSelector: [
+            "CallExpression[callee.property.name='reduce']",
+            "CallExpression[callee.property.name='map']",
+          ],
+        },
+      ],
+    ],
+  },
 ];
 
 export default tests;