fix(core): process static imports

Enable static imports resolution using `baseUrl` in `tsconfig.json`

This update allows resolving static imports when the `baseUrl` property
is set in `tsconfig.json`. For example, `import { foo } from 'app/main.ts'`
can be resolved easily.

- If `baseUrl` is set to `src`, the path resolves to `./src/app/main.ts`.
- If `baseUrl` is not defined, resolution falls back to checking
  `node_modules`.

package.json

@@ -28,6 +28,7 @@
     "@types/eslint": "^8.4.6",
     "@types/estree": "^1.0.0",
     "@types/node": "18.19.14",
+    "@typescript-eslint/rule-tester": "^8.5.0",
     "@vitest/coverage-v8": "^2.0.3",
     "eslint": "^9.6.0",
     "eslint-config-prettier": "^9.1.0",
@@ -38,7 +39,7 @@
     "prettier": "^3.2.5",
     "ts-node": "10.9.1",
     "typescript": "5.5.3",
-    "typescript-eslint": "8.0.0-alpha.41",
+    "typescript-eslint": "^8.5.0",
     "vitest": "^2.0.3"
   }
 }

packages/core/src/lib/file-info/generate-ts-data.ts

@@ -1,7 +1,7 @@
 import getFs, { isFsVirtualised } from '../fs/getFs';
 import * as ts from 'typescript';
 import { TsData } from './ts-data';
-import { getTsPathsAndRootDir } from './get-ts-paths-and-root-dir';
+import { getTsConfigContext } from './get-ts-config-context';
 import { FsPath, toFsPath } from './fs-path';
 
 /**
@@ -23,7 +23,7 @@ import { FsPath, toFsPath } from './fs-path';
  * This will return a paths property of `{'app/*': './src/app'}`
  */
 export const generateTsData = (tsConfigPath: FsPath): TsData => {
-  const { paths, rootDir } = getTsPathsAndRootDir(tsConfigPath);
+  const configContext = getTsConfigContext(tsConfigPath);
 
   const fs = getFs();
   const cwd = fs.getParent(tsConfigPath);
@@ -38,7 +38,7 @@ export const generateTsData = (tsConfigPath: FsPath): TsData => {
 
   const sys = getTsSys();
 
-  return { paths, configObject, cwd, sys, rootDir };
+  return {  ...configContext, configObject, cwd, sys};
 };
 
 function getTsSys(): ts.System {

packages/core/src/lib/file-info/generate-unassigned-file-info.ts

@@ -1,9 +1,9 @@
 import UnassignedFileInfo from './unassigned-file-info';
-import traverseFilesystem from './traverse-filesystem';
 import { FsPath } from './fs-path';
 import { formatFileInfo } from './format-file-info';
 import { logger } from '../log';
 import { TsData } from './ts-data';
+import { traverseFilesystem } from "./traverse-filesystem";
 
 const log = logger('core.file-info.generate-and-root-dir');
 

packages/core/src/lib/file-info/get-ts-paths-and-root-dir.ts → packages/core/src/lib/file-info/get-ts-config-context.ts

@@ -4,22 +4,35 @@ import { FsPath, toFsPath } from './fs-path';
 import { TsConfig } from './ts-config';
 import { InvalidPathError } from '../error/user-error';
 
+export type TsConfigContext = {
+  paths: Record<string, FsPath>;
+  rootDir: FsPath;
+  baseUrl?: FsPath;
+};
+
 /**
- * Retrieves the paths variable from a tsconfig and also traverses through
- * potential parent configs.
+ * Parses the tsconfig.json file and returns specific information for
+ * further processing.
+ *
+ * Maps paths from the tsconfig.json to `FilePath` where possible.
+ * It also traverses through potential parent configs.
+ * It also resolves the `baseUrl` - if present - to an `FsPath`.
  *
  * If there are wildcards, the wildcard will be removed from their path value.
- * This is necessary to keep up the FsPath type
+ * This is necessary to keep up the FsPath type.
+ *
+ * It matters, if a `baseUrl` exists or not. It is not by default set to
+ * the root directory of the tsconfig.json. That has implications for the
+ * TypeScript resolution because static imports only work with a `baseUrl`.
  *
  * @param tsConfigPath path of the tsconfig.json
  */
-export const getTsPathsAndRootDir = (
-  tsConfigPath: FsPath,
-): { paths: Record<string, FsPath>; rootDir: FsPath } => {
+export function getTsConfigContext(tsConfigPath: FsPath): TsConfigContext {
   const fs = getFs();
   let currentTsConfigPath = tsConfigPath;
   let currentTsConfigDir = fs.getParent(currentTsConfigPath);
   const paths: Record<string, FsPath> = {};
+  let baseUrl: FsPath | undefined = undefined;
 
   while (currentTsConfigPath) {
     const configRawContent = fs.readFile(currentTsConfigPath);
@@ -29,16 +42,18 @@ export const getTsPathsAndRootDir = (
     );
 
     const config = configContent.config as TsConfig;
-    const baseUrl = config.compilerOptions?.baseUrl ?? './';
+    currentTsConfigDir = fs.getParent(currentTsConfigPath);
+    if (baseUrl === undefined && config.compilerOptions?.baseUrl) {
+      baseUrl = toFsPath(fs.join(currentTsConfigDir, config.compilerOptions.baseUrl))
+    }
 
     const newPaths: Record<string, string[]> =
       config.compilerOptions?.paths ?? {};
-    currentTsConfigDir = fs.getParent(currentTsConfigPath);
     for (const [key, [value]] of Object.entries(newPaths)) {
       const valueForFsPath = value.endsWith('/*') ? value.slice(0, -2) : value;
       const potentialFilename = fs.join(
         currentTsConfigDir,
-        baseUrl,
+        config.compilerOptions?.baseUrl ?? './',
         valueForFsPath,
       );
       if (fs.exists(potentialFilename)) {
@@ -62,5 +77,9 @@ export const getTsPathsAndRootDir = (
     }
   }
 
-  return { paths, rootDir: currentTsConfigDir };
-};
+  return {
+    paths,
+    rootDir: currentTsConfigDir,
+    baseUrl
+  };
+}

packages/core/src/lib/file-info/fs-path.spec.ts → packages/core/src/lib/file-info/tests/fs-path.spec.ts

@@ -1,7 +1,7 @@
-import { beforeAll, beforeEach, describe, expect, it } from 'vitest';
-import getFs, { useDefaultFs, useVirtualFs } from '../fs/getFs';
-import { Fs } from '../fs/fs';
-import { isFsPath, toFsPath } from './fs-path';
+import getFs, { useDefaultFs, useVirtualFs } from '../../fs/getFs';
+import { Fs } from '../../fs/fs';
+import { isFsPath, toFsPath } from '../fs-path';
+import { describe, beforeEach, beforeAll, it, expect } from 'vitest';
 
 describe('FsPath', () => {
   describe('VirtualFs', () => {
@@ -37,6 +37,6 @@ describe('FsPath', () => {
   it('should also allow a directory', () => {
     useDefaultFs();
     const fs = getFs();
-    expect(isFsPath(fs.join(__dirname, '../test'))).toBe(true);
+    expect(isFsPath(fs.join(__dirname, '../tests'))).toBe(true);
   });
 });

packages/core/src/lib/file-info/generate-ts-data.spec.ts → packages/core/src/lib/file-info/tests/generate-ts-data.spec.ts

@@ -1,10 +1,10 @@
-import { createProject } from '../test/project-creator';
-import { generateTsData } from './generate-ts-data';
-import { describe, it, test, expect } from 'vitest';
-import { FileTree } from '../test/project-configurator';
-import { toFsPath } from './fs-path';
-import { TsPaths } from './ts-data';
-import { tsConfig } from '../test/fixtures/ts-config';
+import { createProject } from '../../test/project-creator';
+import { generateTsData } from '../generate-ts-data';
+import { FileTree } from '../../test/project-configurator';
+import { toFsPath } from '../fs-path';
+import { TsPaths } from '../ts-data';
+import { tsConfig } from '../../test/fixtures/ts-config';
+import { describe, it, expect, test } from 'vitest';
 
 describe('generateTsData', () => {
   function setup(

packages/core/src/lib/file-info/generate-unassigned-file-info.spec.ts → packages/core/src/lib/file-info/tests/generate-unassigned-file-info.spec.ts

@@ -1,11 +1,11 @@
-import { describe, expect, it } from 'vitest';
-import { generateUnassignedFileInfo } from './generate-unassigned-file-info';
-import { createProject } from '../test/project-creator';
-import { inVfs } from '../test/in-vfs';
-import { toFsPath } from './fs-path';
-import { generateTsData } from './generate-ts-data';
-import getFs from '../fs/getFs';
-import { tsConfig } from '../test/fixtures/ts-config';
+import { generateUnassignedFileInfo } from '../generate-unassigned-file-info';
+import { createProject } from '../../test/project-creator';
+import { inVfs } from '../../test/in-vfs';
+import { toFsPath } from '../fs-path';
+import { generateTsData } from '../generate-ts-data';
+import getFs from '../../fs/getFs';
+import { tsConfig } from '../../test/fixtures/ts-config';
+import { describe, it, expect } from 'vitest';
 
 describe('Generate File Info', () => {
   const getTsData = () =>