feat!: Start using enhanced-resolve to improve ts support

lib/rules/file-extension-in-import.js

@@ -15,14 +15,14 @@ const visitImport = require("../util/visit-import")
  * @returns {string[]} File extensions.
  */
 function getExistingExtensions(filePath) {
-    const basename = path.basename(filePath, path.extname(filePath))
+    const directory = path.dirname(filePath)
+    const extension = path.extname(filePath)
+    const basename = path.basename(filePath, extension)
+
     try {
         return fs
-            .readdirSync(path.dirname(filePath))
-            .filter(
-                filename =>
-                    path.basename(filename, path.extname(filename)) === basename
-            )
+            .readdirSync(directory)
+            .filter(filename => filename.startsWith(`${basename}.`))
             .map(filename => path.extname(filename))
     } catch (_error) {
         return []
@@ -74,47 +74,56 @@ module.exports = {
             }
 
             // Get extension.
-            const originalExt = path.extname(name)
-            const existingExts = getExistingExtensions(filePath)
-            const ext = path.extname(filePath) || existingExts.join(" or ")
-            const style = overrideStyle[ext] || defaultStyle
+            const currentExt = path.extname(name)
+            const actualExt = path.extname(filePath)
+            const style = overrideStyle[actualExt] || defaultStyle
+
+            const expectedExt = mapTypescriptExtension(
+                context,
+                filePath,
+                actualExt
+            )
 
             // Verify.
-            if (style === "always" && ext !== originalExt) {
-                const fileExtensionToAdd = mapTypescriptExtension(
-                    context,
-                    filePath,
-                    ext
-                )
+            if (style === "always" && currentExt !== expectedExt) {
                 context.report({
                     node,
                     messageId: "requireExt",
-                    data: { ext: fileExtensionToAdd },
+                    data: { ext: expectedExt },
                     fix(fixer) {
-                        if (existingExts.length !== 1) {
-                            return null
-                        }
                         const index = node.range[1] - 1
                         return fixer.insertTextBeforeRange(
                             [index, index],
-                            fileExtensionToAdd
+                            expectedExt
                         )
                     },
                 })
-            } else if (style === "never" && ext === originalExt) {
+            }
+
+            if (
+                style === "never" &&
+                currentExt !== "" &&
+                expectedExt !== "" &&
+                currentExt === expectedExt
+            ) {
+                const otherExtensions = getExistingExtensions(filePath)
+
+                let fix = fixer => {
+                    const index = name.lastIndexOf(currentExt)
+                    const start = node.range[0] + 1 + index
+                    const end = start + currentExt.length
+                    return fixer.removeRange([start, end])
+                }
+
+                if (otherExtensions.length > 1) {
+                    fix = undefined
+                }
+
                 context.report({
                     node,
                     messageId: "forbidExt",
-                    data: { ext },
-                    fix(fixer) {
-                        if (existingExts.length !== 1) {
-                            return null
-                        }
-                        const index = name.lastIndexOf(ext)
-                        const start = node.range[0] + 1 + index
-                        const end = start + ext.length
-                        return fixer.removeRange([start, end])
-                    },
+                    data: { ext: currentExt },
+                    fix,
                 })
             }
         }

lib/rules/no-hide-core-modules.js

@@ -9,11 +9,6 @@
 "use strict"
 
 const path = require("path")
-const resolve = require("resolve")
-const { pathToFileURL, fileURLToPath } = require("url")
-const {
-    defaultResolve: importResolve,
-} = require("../converted-esm/import-meta-resolve")
 const getPackageJson = require("../util/get-package-json")
 const mergeVisitorsInPlace = require("../util/merge-visitors-in-place")
 const visitImport = require("../util/visit-import")
@@ -29,15 +24,17 @@ const CORE_MODULES = new Set([
     "crypto",
     "dgram",
     "dns",
-    /* "domain", */ "events",
+    /* "domain", */
+    "events",
     "fs",
     "http",
     "https",
     "module",
     "net",
     "os",
     "path",
-    /* "punycode", */ "querystring",
+    /* "punycode", */
+    "querystring",
     "readline",
     "repl",
     "stream",
@@ -132,22 +129,8 @@ module.exports = {
                             continue
                         }
 
-                        let resolved = ""
-                        const moduleId = `${name}/`
-                        try {
-                            resolved = resolve.sync(moduleId, {
-                                basedir: dirPath,
-                            })
-                        } catch (_error) {
-                            try {
-                                const { url } = importResolve(moduleId, {
-                                    parentURL: pathToFileURL(dirPath).href,
-                                })
-
-                                resolved = fileURLToPath(url)
-                            } catch (_error) {
-                                continue
-                            }
+                        if (target.filePath == null) {
+                            continue
                         }
 
                         context.report({
@@ -156,7 +139,7 @@ module.exports = {
                             messageId: "unexpectedImport",
                             data: {
                                 name: path
-                                    .relative(dirPath, resolved)
+                                    .relative(dirPath, target.filePath)
                                     .replace(BACK_SLASH, "/"),
                             },
                         })

lib/util/check-existence.js

@@ -10,50 +10,72 @@ const getAllowModules = require("./get-allow-modules")
 const isTypescript = require("./is-typescript")
 const mapTypescriptExtension = require("../util/map-typescript-extension")
 
+/**
+ * Reports a missing file from ImportTarget
+ * @param {RuleContext} context - A context to report.
+ * @param {import('../util/import-target.js')} target - A list of target information to check.
+ * @returns {void}
+ */
+function markMissing(context, target) {
+    context.report({
+        node: target.node,
+        loc: target.node.loc,
+        messageId: "notFound",
+        data: target,
+    })
+}
+
 /**
  * Checks whether or not each requirement target exists.
  *
  * It looks up the target according to the logic of Node.js.
  * See Also: https://nodejs.org/api/modules.html
  *
  * @param {RuleContext} context - A context to report.
- * @param {ImportTarget[]} targets - A list of target information to check.
+ * @param {import('../util/import-target.js')[]} targets - A list of target information to check.
  * @returns {void}
  */
 exports.checkExistence = function checkExistence(context, targets) {
     const allowed = new Set(getAllowModules(context))
 
     for (const target of targets) {
-        const missingModule =
+        if (
             target.moduleName != null &&
             !allowed.has(target.moduleName) &&
             target.filePath == null
+        ) {
+            markMissing(context, target)
+            continue
+        }
+
+        if (target.moduleName != null) {
+            continue
+        }
+
+        let missingFile =
+            target.filePath == null ? false : !exists(target.filePath)
 
-        let missingFile = target.moduleName == null && !exists(target.filePath)
         if (missingFile && isTypescript(context)) {
             const parsed = path.parse(target.filePath)
+            const pathWithoutExt = path.resolve(parsed.dir, parsed.name)
+
             const reversedExts = mapTypescriptExtension(
                 context,
                 target.filePath,
                 parsed.ext,
                 true
             )
             const reversedPaths = reversedExts.map(
-                reversedExt =>
-                    path.resolve(parsed.dir, parsed.name) + reversedExt
+                reversedExt => pathWithoutExt + reversedExt
             )
             missingFile = reversedPaths.every(
                 reversedPath =>
                     target.moduleName == null && !exists(reversedPath)
             )
         }
-        if (missingModule || missingFile) {
-            context.report({
-                node: target.node,
-                loc: target.node.loc,
-                messageId: "notFound",
-                data: target,
-            })
+
+        if (missingFile) {
+            markMissing(context, target)
         }
     }
 }

lib/util/check-publish.js

@@ -59,7 +59,7 @@ exports.checkPublish = function checkPublish(context, filePath, targets) {
                 if (target.moduleName != null) {
                     return false
                 }
-                const relativeTargetPath = toRelative(target.filePath)
+                const relativeTargetPath = toRelative(target.filePath ?? "")
                 return (
                     relativeTargetPath !== "" &&
                     npmignore.match(relativeTargetPath)
@@ -70,6 +70,7 @@ exports.checkPublish = function checkPublish(context, filePath, targets) {
                 devDependencies.has(target.moduleName) &&
                 !dependencies.has(target.moduleName) &&
                 !allowed.has(target.moduleName)
+
             if (isPrivateFile() || isDevPackage()) {
                 context.report({
                     node: target.node,

lib/util/exists.js

@@ -38,6 +38,10 @@ function existsCaseSensitive(filePath) {
  * @returns {boolean} `true` if the file of a given path exists.
  */
 module.exports = function exists(filePath) {
+    if (filePath == null) {
+        return false
+    }
+
     let result = cache.get(filePath)
     if (result == null) {
         try {

lib/util/get-try-extensions.js

@@ -4,7 +4,26 @@
  */
 "use strict"
 
-const DEFAULT_VALUE = Object.freeze([".js", ".json", ".node"])
+const { getTSConfigForContext } = require("./get-tsconfig")
+const isTypescript = require("./is-typescript")
+
+const DEFAULT_JS_VALUE = Object.freeze([
+    ".js",
+    ".json",
+    ".node",
+    ".mjs",
+    ".cjs",
+])
+const DEFAULT_TS_VALUE = Object.freeze([
+    ".js",
+    ".ts",
+    ".mjs",
+    ".mts",
+    ".cjs",
+    ".cts",
+    ".json",
+    ".node",
+])
 
 /**
  * Gets `tryExtensions` property from a given option object.
@@ -13,7 +32,7 @@ const DEFAULT_VALUE = Object.freeze([".js", ".json", ".node"])
  * @returns {string[]|null} The `tryExtensions` value, or `null`.
  */
 function get(option) {
-    if (option && option.tryExtensions && Array.isArray(option.tryExtensions)) {
+    if (Array.isArray(option?.tryExtensions)) {
         return option.tryExtensions.map(String)
     }
     return null
@@ -24,19 +43,29 @@ function get(option) {
  *
  * 1. This checks `options` property, then returns it if exists.
  * 2. This checks `settings.n` | `settings.node` property, then returns it if exists.
- * 3. This returns `[".js", ".json", ".node"]`.
+ * 3. This returns `[".js", ".json", ".node", ".mjs", ".cjs"]`.
  *
  * @param {RuleContext} context - The rule context.
  * @returns {string[]} A list of extensions.
  */
 module.exports = function getTryExtensions(context, optionIndex = 0) {
-    return (
-        get(context.options && context.options[optionIndex]) ||
-        get(
-            context.settings && (context.settings.n || context.settings.node)
-        ) ||
-        DEFAULT_VALUE
-    )
+    const configured =
+        get(context.options?.[optionIndex]) ??
+        get(context.settings?.n) ??
+        get(context.settings?.node)
+
+    if (configured != null) {
+        return configured
+    }
+
+    if (isTypescript(context)) {
+        const tsconfig = getTSConfigForContext(context)
+        if (tsconfig?.config?.compilerOptions?.allowImportingTsExtensions) {
+            return DEFAULT_TS_VALUE
+        }
+    }
+
+    return DEFAULT_JS_VALUE
 }
 
 module.exports.schema = {

lib/util/get-tsconfig.js

@@ -17,15 +17,33 @@ function getTSConfig(filename) {
  * Attempts to get the ExtensionMap from the tsconfig of a given file.
  *
  * @param {string} filename - The path to the file we need to find the tsconfig.json of
- * @returns {import("get-tsconfig").TsConfigResult}
+ * @returns {import("get-tsconfig").TsConfigResult | null}
  */
 function getTSConfigForFile(filename) {
     return getTsconfig(filename, "tsconfig.json", fsCache)
 }
 
+/**
+ * Attempts to get the ExtensionMap from the tsconfig of a given file.
+ *
+ * @param {import('eslint').Rule.RuleContext} context - The current eslint context
+ * @returns {import("get-tsconfig").TsConfigResult | null}
+ */
+function getTSConfigForContext(context) {
+    // TODO: remove context.get(PhysicalFilename|Filename) when dropping eslint < v10
+    const filename =
+        context.physicalFilename ??
+        context.getPhysicalFilename?.() ??
+        context.filename ??
+        context.getFilename?.()
+
+    return getTSConfigForFile(filename)
+}
+
 module.exports = {
     getTSConfig,
     getTSConfigForFile,
+    getTSConfigForContext,
 }
 
 module.exports.schema = { type: "string" }