Adds support for "typesVersions" redirects

src/compiler/checker.ts

@@ -2276,7 +2276,7 @@ namespace ts {
                         ? Diagnostics.If_the_0_package_actually_exposes_this_module_consider_sending_a_pull_request_to_amend_https_Colon_Slash_Slashgithub_com_SlashDefinitelyTyped_SlashDefinitelyTyped_Slashtree_Slashmaster_Slashtypes_Slash_1
                         : Diagnostics.Try_npm_install_types_Slash_1_if_it_exists_or_add_a_new_declaration_d_ts_file_containing_declare_module_0,
                     packageId.name,
-                    getMangledNameForScopedPackage(packageId.name))
+                    mangleScopedPackageName(packageId.name))
                 : undefined;
             errorOrSuggestion(isError, errorNode, chainDiagnosticMessages(
                 errorInfo,

src/compiler/core.ts

@@ -65,6 +65,7 @@ namespace ts {
 
 /* @internal */
 namespace ts {
+    export const emptyArray: never[] = [] as never[];
 
     /** Create a MapLike with good performance. */
     function createDictionaryObject<T>(): MapLike<T> {

src/compiler/diagnosticMessages.json

@@ -3274,7 +3274,7 @@
         "category": "Message",
         "code": 6104
     },
-    "Expected type of '{0}' field in 'package.json' to be 'string', got '{1}'.": {
+    "Expected type of '{0}' field in 'package.json' to be '{1}', got '{2}'.": {
         "category": "Message",
         "code": 6105
     },
@@ -3672,6 +3672,18 @@
         "category": "Error",
         "code": 6205
     },
+    "'package.json' has a 'typesVersions' field with version-specific path mappings.": {
+        "category": "Message",
+        "code": 6206
+    },
+    "'package.json' does not have a 'typesVersions' entry that matches version '{0}'.": {
+        "category": "Message",
+        "code": 6207
+    },
+    "'package.json' has a 'typesVersions' entry '{0}' that matches compiler version '{1}', looking for a pattern to match module name '{2}'.": {
+        "category": "Message",
+        "code": 6208
+    },
 
     "Projects to reference": {
         "category": "Message",

src/compiler/moduleSpecifiers.ts

@@ -273,7 +273,8 @@ namespace ts.moduleSpecifiers {
                     const suffix = pattern.substr(indexOfStar + 1);
                     if (relativeToBaseUrl.length >= prefix.length + suffix.length &&
                         startsWith(relativeToBaseUrl, prefix) &&
-                        endsWith(relativeToBaseUrl, suffix)) {
+                        endsWith(relativeToBaseUrl, suffix) ||
+                        !suffix && relativeToBaseUrl === removeTrailingDirectorySeparator(prefix)) {
                         const matchedStar = relativeToBaseUrl.substr(prefix.length, relativeToBaseUrl.length - suffix.length);
                         return key.replace("*", matchedStar);
                     }
@@ -302,6 +303,26 @@ namespace ts.moduleSpecifiers {
             return undefined;
         }
 
+        const packageRootPath = moduleFileName.substring(0, parts.packageRootIndex);
+        const packageJsonPath = combinePaths(packageRootPath, "package.json");
+        const packageJsonContent = host.fileExists!(packageJsonPath)
+            ? JSON.parse(host.readFile!(packageJsonPath)!)
+            : undefined;
+        const versionPaths = packageJsonContent && packageJsonContent.typesVersions
+            ? getPackageJsonTypesVersionsPaths(packageJsonContent.typesVersions)
+            : undefined;
+        if (versionPaths) {
+            const subModuleName = moduleFileName.slice(parts.packageRootIndex + 1);
+            const fromPaths = tryGetModuleNameFromPaths(
+                removeFileExtension(subModuleName),
+                removeExtensionAndIndexPostFix(subModuleName, Ending.Minimal, options),
+                versionPaths.paths
+            );
+            if (fromPaths !== undefined) {
+                moduleFileName = combinePaths(moduleFileName.slice(0, parts.packageRootIndex), fromPaths);
+            }
+        }
+
         // Simplify the full file path to something that can be resolved by Node.
 
         // If the module could be imported by a directory name, use that directory's name
@@ -312,23 +333,18 @@ namespace ts.moduleSpecifiers {
 
         // If the module was found in @types, get the actual Node package name
         const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
-        const packageName = getPackageNameFromAtTypesDirectory(nodeModulesDirectoryName);
+        const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
         // For classic resolution, only allow importing from node_modules/@types, not other node_modules
         return getEmitModuleResolutionKind(options) !== ModuleResolutionKind.NodeJs && packageName === nodeModulesDirectoryName ? undefined : packageName;
 
         function getDirectoryOrExtensionlessFileName(path: string): string {
             // If the file is the main module, it can be imported by the package name
-            const packageRootPath = path.substring(0, parts.packageRootIndex);
-            const packageJsonPath = combinePaths(packageRootPath, "package.json");
-            if (host.fileExists!(packageJsonPath)) { // TODO: GH#18217
-                const packageJsonContent = JSON.parse(host.readFile!(packageJsonPath)!);
-                if (packageJsonContent) {
-                    const mainFileRelative = packageJsonContent.typings || packageJsonContent.types || packageJsonContent.main;
-                    if (mainFileRelative) {
-                        const mainExportFile = toPath(mainFileRelative, packageRootPath, getCanonicalFileName);
-                        if (removeFileExtension(mainExportFile) === removeFileExtension(getCanonicalFileName(path))) {
-                            return packageRootPath;
-                        }
+            if (packageJsonContent) {
+                const mainFileRelative = packageJsonContent.typings || packageJsonContent.types || packageJsonContent.main;
+                if (mainFileRelative) {
+                    const mainExportFile = toPath(mainFileRelative, packageRootPath, getCanonicalFileName);
+                    if (removeFileExtension(mainExportFile) === removeFileExtension(getCanonicalFileName(path))) {
+                        return packageRootPath;
                     }
                 }
             }