feat: add CustomRuleVisitorWithExit type to @eslint/plugin-kit

packages/plugin-kit/src/source-code.js

@@ -22,6 +22,11 @@
  * @typedef {import("@eslint/core").TextSourceCode<Options>} TextSourceCode<Options>
  * @template {SourceCodeBaseTypeOptions} [Options=SourceCodeBaseTypeOptions]
  */
+/** @typedef {import("@eslint/core").RuleVisitor} RuleVisitor */
+/**
+ * @typedef {import("./types.ts").CustomRuleVisitorWithExit<RuleVisitorType>} CustomRuleVisitorWithExit<RuleVisitorType>
+ * @template {RuleVisitor} RuleVisitorType
+ */
 
 //-----------------------------------------------------------------------------
 // Helpers

packages/plugin-kit/src/types.ts

@@ -3,5 +3,31 @@
  * @author Nicholas C. Zakas
  */
 
+//------------------------------------------------------------------------------
+// Imports
+//------------------------------------------------------------------------------
+
+import type { RuleVisitor } from "@eslint/core";
+
+//------------------------------------------------------------------------------
+// Exports
+//------------------------------------------------------------------------------
+
+/**
+ * Adds matching `:exit` selector properties for each key of a `RuleVisitor`.
+ */
+export type CustomRuleVisitorWithExit<RuleVisitorType extends RuleVisitor> = {
+	[Key in keyof RuleVisitorType as
+		| Key
+		| `${Key & string}:exit`]: RuleVisitorType[Key];
+};
+
+/**
+ * A map of names to string values, or `null` when no value is provided.
+ */
 export type StringConfig = Record<string, string | null>;
+
+/**
+ * A map of names to boolean flags.
+ */
 export type BooleanConfig = Record<string, boolean>;

packages/plugin-kit/tests/types/types.test.ts

@@ -8,15 +8,16 @@
 //-----------------------------------------------------------------------------
 
 import {
-	BooleanConfig,
+	type BooleanConfig,
 	CallMethodStep,
 	ConfigCommentParser,
+	type CustomRuleVisitorWithExit,
 	Directive,
-	DirectiveType,
-	RulesConfig,
-	SourceLocation,
-	SourceRange,
-	StringConfig,
+	type DirectiveType,
+	type RulesConfig,
+	type SourceLocation,
+	type SourceRange,
+	type StringConfig,
 	TextSourceCodeBase,
 	VisitNodeStep,
 } from "@eslint/plugin-kit";
@@ -182,3 +183,41 @@ step1.kind satisfies 1;
 step1.phase satisfies 1 | 2;
 step1.target satisfies object;
 step1.type satisfies "visit";
+
+type TestVisitor = {
+	Program: (node: { type: "Program" }) => void;
+	Identifier: (node: { type: "Identifier"; name: string }) => void;
+	"FunctionDeclaration > Identifier": (node: { type: "Identifier" }) => void;
+};
+
+type VisitorWithExit = CustomRuleVisitorWithExit<TestVisitor>;
+
+const visitor: VisitorWithExit = {
+	Program(node) {
+		node.type satisfies "Program";
+	},
+	Identifier(node) {
+		node.type satisfies "Identifier";
+		node.name satisfies string;
+	},
+	"FunctionDeclaration > Identifier"(node) {
+		node.type satisfies "Identifier";
+	},
+	"Program:exit"(node) {
+		node.type satisfies "Program";
+	},
+	"Identifier:exit"(node) {
+		node.type satisfies "Identifier";
+		node.name satisfies string;
+	},
+	"FunctionDeclaration > Identifier:exit"(node) {
+		node.type satisfies "Identifier";
+	},
+	// @ts-expect-error -- Extra keys should not be allowed
+	Foo() {},
+};
+
+visitor.Program satisfies TestVisitor["Program"];
+visitor["Program:exit"] satisfies TestVisitor["Program"];
+// @ts-expect-error -- Exit key must correspond to an existing selector
+visitor["Expression:exit"] = () => {};

tools/build-cts.js

@@ -24,9 +24,6 @@ if (!newFilename) {
 }
 
 const oldSourceText = await readFile(filename, "utf-8");
-const newSourceText = oldSourceText.replaceAll(
-	' from "./types.ts";\n',
-	' from "./types.cts";\n',
-);
+const newSourceText = oldSourceText.replaceAll('"./types.ts"', '"./types.cts"');
 
 await writeFile(newFilename, newSourceText);