feat: add ESLint v9 compatibility layer

lib/eslint-compat.js

@@ -0,0 +1,22 @@
+"use strict"
+
+function getDeclaredVariables(context, node) {
+ return (
+ getSourceCode(context).getDeclaredVariables?.(node) ??
+ context.getDeclaredVariables(node)
+ )
+}
+
+function getSourceCode(context) {
+ return context.sourceCode ?? context.getSourceCode()
+}
+
+function getScope(context, node) {
+ return getSourceCode(context).getScope?.(node) ?? context.getScope()
+}
+
+module.exports = {
+ getDeclaredVariables,
+ getSourceCode,
+ getScope,
+}

lib/rules/arrow-parens.js

@@ -1,12 +1,9 @@
-/**
- * @author Toru Nagashima
- * @copyright 2015 Toru Nagashima. All rights reserved.
- * See LICENSE file in root directory for full license.
- */
 "use strict"
 
+const { getSourceCode } = require("../eslint-compat")
+
 /**
- * Checks whether or not a given token is `(`.
+ * Checks whether a given token is `(`.
  * @param {Token} token - A token to check.
  * @returns {boolean} `true` when the token is `(`.
  */
@@ -15,7 +12,7 @@ function isOpenParen(token) {
 }
 
 /**
- * Checks whether or not given two tokens are at a same line.
+ * Checks whether given two tokens are at a same line.
  * @param {Token} a - A left token.
  * @param {Token} b - A right token.
  * @returns {boolean} `true` when the tokens are at a same line.
@@ -43,12 +40,11 @@ module.exports = {
  type: "suggestion",
  },
  create(context) {
+ const sourceCode = getSourceCode(context)
  return {
  ArrowFunctionExpression(node) {
- const first = context
- .getSourceCode()
- .getFirstToken(node, node.async ? 1 : 0)
- const before = context.getSourceCode().getTokenBefore(first)
+ const first = sourceCode.getFirstToken(node, node.async ? 1 : 0)
+ const before = sourceCode.getTokenBefore(first)
 
  if (isOpenParen(first)) {
  if (
@@ -63,9 +59,8 @@ module.exports = {
  fix(fixer) {
  const id = node.params[0]
  const begin = first.range[0]
- const end = context
- .getSourceCode()
- .getTokenAfter(id).range[1]
+ const end =
+ sourceCode.getTokenAfter(id).range[1]
 
  return fixer.replaceTextRange(
  [begin, end],

lib/rules/block-scoped-var.js

@@ -1,10 +1,7 @@
-/**
- * @author Toru Nagashima
- * @copyright 2015 Toru Nagashima. All rights reserved.
- * See LICENSE file in root directory for full license.
- */
 "use strict"
 
+const { getDeclaredVariables } = require("../eslint-compat")
+
 //------------------------------------------------------------------------------
 // Helpers
 //------------------------------------------------------------------------------
@@ -15,7 +12,7 @@ const containerNodeType =
  /^(?:For(?:In|Of)?Statement|(?:Arrow)?Function(?:Declaration|Expression))$/u
 
 /**
- * Checks whether or not a given definition should be skipped.
+ * Checks whether a given definition should be skipped.
  * @param {escope.Variable.DefEntry} def - A definition to check.
  * @param {escope.Variable.DefEntry[]} defs - A definition list which includes `def`.
  * @param {escope.Variable} variable - A variable which is defined by the definition.
@@ -180,7 +177,7 @@ class PseudoScope {
  }
 
  /**
- * Turns an used flag on.
+ * Turns a used flag on.
  * @returns {void}
  */
  markAsUsed() {
@@ -213,12 +210,12 @@ module.exports = {
  },
  create(context) {
  /**
- * Finds and reports references which are outside of valid scopes.
+ * Finds and reports references which are outside valid scopes.
  * @param {ASTNode} node - A node to get variables.
  * @returns {void}
  */
  function checkForVariables(node) {
- const variables = context.getDeclaredVariables(node)
+ const variables = getDeclaredVariables(context, node)
  for (const variable of variables) {
  const defs = variable.defs
  const lastDef = defs[defs.length - 1]
@@ -235,7 +232,7 @@ module.exports = {
  continue
  }
 
- // Check whether or not any reading reference exists.
+ // Check whether any reading reference exists.
  // And while it does, warn references which does not belong to any
  // scope.
  let hasReadRef = false

lib/rules/no-instanceof-array.js

@@ -1,10 +1,7 @@
-/**
- * @author Toru Nagashima
- * @copyright 2016 Toru Nagashima. All rights reserved.
- * See LICENSE file in root directory for full license.
- */
 "use strict"
 
+const { getScope, getSourceCode } = require("../eslint-compat")
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -26,7 +23,7 @@ module.exports = {
  },
 
  create(context) {
- const sourceCode = context.getSourceCode()
+ const sourceCode = getSourceCode(context)
 
  /**
  * Checks whether the given node is RHS of instanceof.
@@ -43,8 +40,8 @@ module.exports = {
  }
 
  return {
- "Program:exit"() {
- const globalScope = context.getScope()
+ "Program:exit"(globalNode) {
+ const globalScope = getScope(context, globalNode)
  const variable = globalScope.set.get("Array")
 
  // Skip if undefined or shadowed

lib/rules/no-instanceof-wrapper.js

@@ -1,10 +1,7 @@
-/**
- * @author Toru Nagashima
- * @copyright 2016 Toru Nagashima. All rights reserved.
- * See LICENSE file in root directory for full license.
- */
 "use strict"
 
+const { getScope, getSourceCode } = require("../eslint-compat")
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -26,7 +23,7 @@ module.exports = {
  },
 
  create(context) {
- const sourceCode = context.getSourceCode()
+ const sourceCode = getSourceCode(context)
  const targetTypes = [
  "Boolean",
  "Number",
@@ -51,8 +48,8 @@ module.exports = {
  }
 
  return {
- "Program:exit"() {
- const globalScope = context.getScope()
+ "Program:exit"(globalNode) {
+ const globalScope = getScope(context, globalNode)
 
  for (const ctorName of targetTypes) {
  const typeName = ctorName.toLowerCase()

lib/rules/no-this-in-static.js

@@ -1,10 +1,7 @@
-/**
- * @author Toru Nagashima
- * @copyright 2016 Toru Nagashima. All rights reserved.
- * See LICENSE file in root directory for full license.
- */
 "use strict"
 
+const { getSourceCode } = require("../eslint-compat")
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -25,7 +22,7 @@ module.exports = {
  },
 
  create(context) {
- const sourceCode = context.getSourceCode()
+ const sourceCode = getSourceCode(context)
  let funcInfo = null
 
  /**
@@ -65,7 +62,7 @@ module.exports = {
  }
 
  /**
- * Reports the `this`/`super` node if this is inside of a static method.
+ * Reports the `this`/`super` node if this is inside a static method.
  *
  * @param {ASTNode} node - The node to report.
  * @returns {void}

lib/rules/no-use-ignored-vars.js

@@ -1,9 +1,7 @@
-/**
- * @fileoverview Rule to disallow a use of ignored variables.
- * @author Toru Nagashima
- */
 "use strict"
 
+const { getScope } = require("../eslint-compat")
+
 //------------------------------------------------------------------------------
 // Helpers
 //------------------------------------------------------------------------------
@@ -84,8 +82,8 @@ module.exports = {
  }
 
  return {
- "Program:exit"() {
- const queue = [context.getScope()]
+ "Program:exit"(node) {
+ const queue = [getScope(context, node)]
  let scope = null
 
  while ((scope = queue.pop()) != null) {

lib/rules/no-useless-rest-spread.js

@@ -1,9 +1,7 @@
-/**
- * @fileoverview Rule to disallow unnecessary spread operators.
- * @author Toru Nagashima
- */
 "use strict"
 
+const { getSourceCode } = require("../eslint-compat")
+
 //------------------------------------------------------------------------------
 // Helpers
 //------------------------------------------------------------------------------
@@ -109,7 +107,7 @@ module.exports = {
  },
 
  create(context) {
- const sourceCode = context.getSourceCode()
+ const sourceCode = getSourceCode(context)
 
  /**
  * Verify the given SpreadElement or RestElement.
@@ -133,12 +131,11 @@ module.exports = {
  const isRestParameter =
  nodeType === "RestElement" && argumentType !== parentType
  const type1 = nodeType === "RestElement" ? "rest" : "spread"
- const type2 =
- /* eslint-disable @eslint-community/mysticatea/prettier */
- isRestParameter ? "parameter" :
- isArray ? "element" :
- /* otherwise */ "property"
- /* eslint-enable @eslint-community/mysticatea/prettier */
+ const type2 = isRestParameter
+ ? "parameter"
+ : isArray
+ ? "element"
+ : /* otherwise */ "property"
 
  context.report({
  node,