diff --git a/resolvewithplus.js b/resolvewithplus.js
index 2f60dcb..b7a55f3 100644
--- a/resolvewithplus.js
+++ b/resolvewithplus.js
@@ -15,6 +15,8 @@ const isRelPathRe = /^.\.?(?=\/|\\)/
 const isWin32PathRe = /\\/g
 const isSupportedIndexRe = /index.[tj]sx?$/
 const isResolveWithPathRe = /[\\/]resolvewithplus[\\/]/
+const isJsExtnRe = /\.js$/
+const isTsExtnRe = /\.ts$/
 const packageNameRe = /(^@[^/]*\/[^/]*|^[^/]*)\/?(.*)$/
 const isESMImportSubpathRe = /^#/
 const esmStrGlobRe = /(\*)/g
@@ -291,8 +293,14 @@ const getasdirsync = (d, opts) => {
   if ((relpath = gettargetindex(jsonobj, opts))) {
     filepath = getasfilesync(path.join(d, relpath))
   } else if ((relpath = jsonobj.main)) {
-    filepath = getasfilesync(path.join(d, relpath))
-      || getasfilesync(path.join(d, path.join(relpath, 'index')))
+    if (opts.isTypescript && isJsExtnRe.test(relpath)) {
+      filepath = getasfilesync(path.join(d, relpath.replace(isJsExtnRe, '.ts')))
+        || getasfilesync(path.join(d, relpath))
+        || getasfilesync(path.join(d, path.join(relpath, 'index')))
+    } else {
+      filepath = getasfilesync(path.join(d, relpath))
+        || getasfilesync(path.join(d, path.join(relpath, 'index')))
+    }
   } else {
     supportedExtensions.some(f => (
       (f = path.join(d, `index${f}`)) && isfilesync(f) && (filepath = f)))
@@ -420,7 +428,7 @@ const begin = (requirepath, withpath, opts) => {
   } else {
     fullpath = isDirPathRe.test(requirepath)
       ? getasfileordir(pathToPosix(requirepath), withpath, opts)
-      : getasnode_module(requirepath, withpath)
+      : getasnode_module(requirepath, withpath, opts)
 
     fullpath = fullpath && (
       opts.isposixpath
@@ -431,11 +439,20 @@ const begin = (requirepath, withpath, opts) => {
   return fullpath
 }
 
+const createopts = (moduleId, parent, opts) => {
+  opts = opts || {}
+  opts.isTypescript = typeof opts.isTypescript === 'boolean'
+    ? opts.isTypescript : isTsExtnRe.test(parent)
+
+  return opts
+}
+
 const resolvewith = (requirepath, withpath, opts) => {
   let resolvedpath = cache[requirepath+withpath]
   if (resolvedpath) return resolvedpath
 
-  resolvedpath = begin(requirepath, withpath, opts || {})
+  opts = createopts(requirepath, withpath, opts)
+  resolvedpath = begin(requirepath, withpath, opts)
 
   return cache[requirepath+withpath] = resolvedpath
 }
diff --git a/tests/tests-basic/package.json b/tests/tests-basic/package.json
index d16d7e3..31b5056 100644
--- a/tests/tests-basic/package.json
+++ b/tests/tests-basic/package.json
@@ -20,7 +20,15 @@
     "nodejsexample_12_exports": "file:nodejsexample_12_exports",
     "resolvewithplus": "file:.."
   },
+  "workspaces": [
+    "workspaces-js/*",
+    "workspaces-ts/*"
+  ],
   "scripts": {
-    "test": "node --experimental-import-meta-resolve --test tests-basic.test.js tests-export-patterns.test.js tests-import-patterns.test.js"
+    "test-workspaces-js": "npm --prefix workspaces-js/js-b test",
+    "test-workspaces-ts": "npm --prefix workspaces-ts/ts-b test",
+    "test-workspaces": "npm run test-workspaces-js && npm run test-workspaces-ts",
+    "test-vanilla": "node --experimental-import-meta-resolve --test tests-basic.test.js tests-export-patterns.test.js tests-import-patterns.test.js",
+    "test": "npm run test-workspaces && npm run test-vanilla"
   }
 }
diff --git a/tests/tests-basic/workspaces-js/js-a/index.js b/tests/tests-basic/workspaces-js/js-a/index.js
new file mode 100644
index 0000000..c970c82
--- /dev/null
+++ b/tests/tests-basic/workspaces-js/js-a/index.js
@@ -0,0 +1,3 @@
+export function foo () {
+  return 'foo'
+}
diff --git a/tests/tests-basic/workspaces-js/js-a/package.json b/tests/tests-basic/workspaces-js/js-a/package.json
new file mode 100644
index 0000000..17e9f94
--- /dev/null
+++ b/tests/tests-basic/workspaces-js/js-a/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "js-a",
+  "version": "0.0.0",
+  "type": "module",
+  "main": "index.js"
+}
diff --git a/tests/tests-basic/workspaces-js/js-b/index.js b/tests/tests-basic/workspaces-js/js-b/index.js
new file mode 100644
index 0000000..cd0f9ec
--- /dev/null
+++ b/tests/tests-basic/workspaces-js/js-b/index.js
@@ -0,0 +1,5 @@
+import {foo} from 'a'
+
+export default function test () {
+  return foo()
+}
diff --git a/tests/tests-basic/workspaces-js/js-b/package.json b/tests/tests-basic/workspaces-js/js-b/package.json
new file mode 100644
index 0000000..835a4db
--- /dev/null
+++ b/tests/tests-basic/workspaces-js/js-b/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "js-b",
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "test": "node --experimental-import-meta-resolve --test"
+  },
+  "dependencies": {
+    "js-a": "^0.0.0"
+  }
+}
diff --git a/tests/tests-basic/workspaces-js/js-b/test.js b/tests/tests-basic/workspaces-js/js-b/test.js
new file mode 100644
index 0000000..e30f2f9
--- /dev/null
+++ b/tests/tests-basic/workspaces-js/js-b/test.js
@@ -0,0 +1,9 @@
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import resolvewithplus from '../../../../resolvewithplus.js'
+
+test('should return workspace paths', () => {
+  assert.strictEqual(
+    import.meta.resolve('js-a'),
+    resolvewithplus('js-a'))
+})
diff --git a/tests/tests-basic/workspaces-ts/ts-a/index.ts b/tests/tests-basic/workspaces-ts/ts-a/index.ts
new file mode 100644
index 0000000..c970c82
--- /dev/null
+++ b/tests/tests-basic/workspaces-ts/ts-a/index.ts
@@ -0,0 +1,3 @@
+export function foo () {
+  return 'foo'
+}
diff --git a/tests/tests-basic/workspaces-ts/ts-a/package.json b/tests/tests-basic/workspaces-ts/ts-a/package.json
new file mode 100644
index 0000000..b197b2f
--- /dev/null
+++ b/tests/tests-basic/workspaces-ts/ts-a/package.json
@@ -0,0 +1,6 @@
+{
+  "name": "ts-a",
+  "version": "0.0.0",
+  "type": "module",
+  "main": "index.js"
+}
diff --git a/tests/tests-basic/workspaces-ts/ts-b/index.ts b/tests/tests-basic/workspaces-ts/ts-b/index.ts
new file mode 100644
index 0000000..cd0f9ec
--- /dev/null
+++ b/tests/tests-basic/workspaces-ts/ts-b/index.ts
@@ -0,0 +1,5 @@
+import {foo} from 'a'
+
+export default function test () {
+  return foo()
+}
diff --git a/tests/tests-basic/workspaces-ts/ts-b/package.json b/tests/tests-basic/workspaces-ts/ts-b/package.json
new file mode 100644
index 0000000..0ba0065
--- /dev/null
+++ b/tests/tests-basic/workspaces-ts/ts-b/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "ts-b",
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "test": "node --loader=ts-node/esm --test test.ts"
+  },
+  "dependencies": {
+    "ts-a": "^0.0.0"
+  },
+  "devDependencies": {
+    "ts-node": "^10.9.1"
+  }
+}
diff --git a/tests/tests-basic/workspaces-ts/ts-b/test.ts b/tests/tests-basic/workspaces-ts/ts-b/test.ts
new file mode 100644
index 0000000..509b072
--- /dev/null
+++ b/tests/tests-basic/workspaces-ts/ts-b/test.ts
@@ -0,0 +1,12 @@
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import resolvewithplus from '../../../../resolvewithplus.js'
+
+console.log('test here!')
+/*
+test('should return workspace paths', () => {
+  assert.strictEqual(
+    import.meta.resolve('ts-a'),
+    resolvewithplus('ts-a'))
+})
+*/
diff --git a/tests/tests-basic/workspaces-ts/ts-b/tsconfig.json b/tests/tests-basic/workspaces-ts/ts-b/tsconfig.json
new file mode 100644
index 0000000..5b17f4e
--- /dev/null
+++ b/tests/tests-basic/workspaces-ts/ts-b/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "esm": true,
+  "compilerOptions": {
+    "allowSyntheticDefaultImports": true,
+    "module": "ESNext",
+    "moduleResolution": "node"
+  }
+}