fix(tsconfig paths): support paths starting with slash (#41)

Author: privatenumber

src/index.ts

@@ -16,7 +16,7 @@ import {
 } from 'get-tsconfig';
 import type { TransformOptions } from 'esbuild';
 
-const isPathPattern = /^\.{0,2}\//;
+const isRelativePathPattern = /^\.{1,2}\//;
 const isTsFilePatten = /\.[cm]?tsx?$/;
 const nodeModulesPath = `${path.sep}node_modules${path.sep}`;
 
@@ -158,7 +158,7 @@ Module._resolveFilename = function (request, parent, isMain, options) {
 		tsconfigPathsMatcher
 
 		// bare specifier
-		&& !isPathPattern.test(request)
+		&& !isRelativePathPattern.test(request)
 
 		// Dependency paths should not be resolved using tsconfig.json
 		&& !parent?.filename?.includes(nodeModulesPath)

tests/fixtures/tsconfig/src/paths-slash-match.ts

@@ -0,0 +1,3 @@
+import value from '/nested-resolve-target';
+
+console.log(value);

tests/fixtures/tsconfig/tsconfig.json

@@ -7,7 +7,8 @@
 		"paths": {
 			"paths-exact-match": ["resolve-target"],
 			"p/*": ["utils/*"],
-			"*/s": ["utils/*"]
+			"*/s": ["utils/*"],
+			"/*": ["utils/*"]
 		},
 	},
 }

tests/index.ts

@@ -2,16 +2,19 @@ import { describe } from 'manten';
 import { createNode } from './utils/node-with-loader.js';
 
 const nodeVersions = [
-	'18',
 	'20',
 	...(
-		process.env.CI
+		(
+			process.env.CI
+			&& process.platform !== 'win32'
+		)
 			? [
 				'12.16.2', // Pre ESM import
 				'12',
 				'14',
 				'16',
 				'17',
+				'18',
 			]
 			: []
 	),

tests/specs/typescript/tsconfig.ts

@@ -143,6 +143,13 @@ export default testSuite(async ({ describe }, node: NodeApis) => {
 				expect(nodeProcess.stdout).toBe('nested-resolve-target');
 			});
 
+			test('resolves paths slash prefix', async () => {
+				const nodeProcess = await node.load('./src/paths-slash-match.ts', {
+					cwd: './tsconfig',
+				});
+				expect(nodeProcess.stdout).toBe('nested-resolve-target');
+			});
+
 			test('resolves paths suffix', async () => {
 				const nodeProcess = await node.load('./src/paths-suffix-match.ts', {
 					cwd: './tsconfig',