diff --git a/CHANGELOG.md b/CHANGELOG.md
index c9764029..f407cd83 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 # changelog
 
+ * 2.5.1 _Sep.13.2023_
+   * [resolve existing ".ts" files,](https://github.com/iambumblehead/esmock/pull/243) rather than ".js" files, when typescript detected, thanks @tpluscode
  * 2.5.0 _Sep.09.2023_
    * [remove duplicate nextLoad call](https://github.com/iambumblehead/esmock/pull/239)
    * [add support for initialize hook](https://github.com/iambumblehead/esmock/pull/240)
diff --git a/package.json b/package.json
index 49428876..9a9dde77 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "esmock",
   "type": "module",
-  "version": "2.5.0",
+  "version": "2.5.1",
   "license": "ISC",
   "readmeFilename": "README.md",
   "description": "provides native ESM import and globals mocking for unit tests",
@@ -60,7 +60,7 @@
     "node": ">=14.16.0"
   },
   "dependencies": {
-    "resolvewithplus": "^2.0.2"
+    "resolvewithplus": "^2.0.4"
   },
   "devDependencies": {
     "c8": "^8.0.1",
diff --git a/tests/local/main.ts b/tests/local/main-ts.ts
similarity index 100%
rename from tests/local/main.ts
rename to tests/local/main-ts.ts
diff --git a/tests/package.json b/tests/package.json
index 44c7d030..63c715f9 100644
--- a/tests/package.json
+++ b/tests/package.json
@@ -43,6 +43,7 @@
     "install:test-no-loader": "cd tests-no-loader && npm install",
     "install:test-nodets": "cd tests-nodets && npm install",
     "install:test-mocha": "cd tests-mocha && npm install",
+    "install:test-workspaces": "cd tests-workspaces && npm install",
     "install:all": "node --version && npm install && npm-run-all install:test*",
     "test:test-uvu": "cd tests-uvu && npm test",
     "test:test-mocha": "cd tests-mocha && npm test",
@@ -55,6 +56,7 @@
     "test:node18-test-nodets": "cd tests-nodets && npm test",
     "test:node18-test-source-map": "cd tests-source-map && npm test",
     "test:node18-test-no-loader": "cd tests-no-loader && npm test",
+    "test:node18-test-workspaces": "cd tests-workspaces && npm test",
     "test:node18:all": "npm run isnodelt18 || npm-run-all test:node18-test*",
     "test:all": "npm-run-all test:test* && npm run test:node18:all",
     "test:all-cover": "c8 --src=../src/* npm run test:all",
diff --git a/tests/tests-FAIL-swc/esmock.node-swc.test.ts b/tests/tests-FAIL-swc/esmock.node-swc.test.ts
index 0248852f..9b739f08 100644
--- a/tests/tests-FAIL-swc/esmock.node-swc.test.ts
+++ b/tests/tests-FAIL-swc/esmock.node-swc.test.ts
@@ -7,7 +7,7 @@ import esmock from 'esmock'
 // when the typescript sytax are removed, tests pass
 
 test('should mock ts when using node-ts', async () => {
-  const main = await esmock('../local/main.ts', {
+  const main = await esmock('../local/main-ts.ts', {
     path: {
       basename: () => 'hellow'
     }
@@ -17,7 +17,7 @@ test('should mock ts when using node-ts', async () => {
 })
 
 test('should mock pg', async () => {
-  const main = await esmock('../local/main.ts', {
+  const main = await esmock('../local/main-ts.ts', {
     'pg': {
       Pool: (config:any) => {
         return config || 'mocked pool'
diff --git a/tests/tests-FAIL-tsx/esmock.node.tsx.test.ts b/tests/tests-FAIL-tsx/esmock.node.tsx.test.ts
index 3211030f..ac032abd 100644
--- a/tests/tests-FAIL-tsx/esmock.node.tsx.test.ts
+++ b/tests/tests-FAIL-tsx/esmock.node.tsx.test.ts
@@ -15,7 +15,7 @@ test('should mock js when using tsx', async () => {
 // tsx fails :/ https://github.com/esbuild-kit/tsx/issues/264
 //
 // test('should mock ts when using tsx - unknown file extension', async () => {
-//   const main = await esmock('../local/main.ts', {
+//   const main = await esmock('../local/main-ts.ts', {
 //     path: {
 //       basename: () => 'hellow'
 //     }
diff --git a/tests/tests-nodets/esmock.node-ts.test.ts b/tests/tests-nodets/esmock.node-ts.test.ts
index cca5049b..45571d3c 100644
--- a/tests/tests-nodets/esmock.node-ts.test.ts
+++ b/tests/tests-nodets/esmock.node-ts.test.ts
@@ -3,7 +3,7 @@ import assert from 'assert'
 import esmock from 'esmock'
 
 test('should mock ts when using node-ts', { only: true }, async () => {
-  const main = await esmock('../local/main.ts', {
+  const main = await esmock('../local/main-ts.ts', {
     path: {
       basename: () => 'hellow'
     }
@@ -26,4 +26,3 @@ test('should mock import global at import tree w/ mixed esm cjs', async () => {
   assert.equal(consolelog.mock.calls[0].arguments[0], 'foo')
   assert.equal(consolelog.mock.calls[1].arguments[0], 'foo')
 })
-
diff --git a/tests/tests-tsm/esmock.node-tsm.test.ts b/tests/tests-tsm/esmock.node-tsm.test.ts
index 9c8085d9..5d591ba2 100644
--- a/tests/tests-tsm/esmock.node-tsm.test.ts
+++ b/tests/tests-tsm/esmock.node-tsm.test.ts
@@ -3,7 +3,7 @@ import assert from 'assert'
 import esmock from 'esmock'
 
 test('should mock ts when using node-ts', async () => {
-  const main = await esmock('../local/main.ts', {
+  const main = await esmock('../local/main-ts.ts', {
     path: {
       basename: () => 'hellow'
     }
@@ -14,7 +14,7 @@ test('should mock ts when using node-ts', async () => {
 })
 
 test('should mock pg', async () => {
-  const main = await esmock('../local/main.ts', {
+  const main = await esmock('../local/main-ts.ts', {
     'pg': {
       Pool: (config:any) => {
         return config || 'mocked pool'
diff --git a/tests/tests-workspaces/package.json b/tests/tests-workspaces/package.json
new file mode 100644
index 00000000..3b91407d
--- /dev/null
+++ b/tests/tests-workspaces/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "esmock unit tests, workspaces",
+  "workspaces": [
+    "workspaces-js/*",
+    "workspaces-ts/*"
+  ],  
+  "scripts": {
+    "isnodelt20_6": "node -e \"(([mj, mn]) => (+mj < 20 || (+mj === 20 && +mn < 6)))(process.versions.node.split('.')) || process.exit(1)\"",
+    "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": "npm run isnodelt20_6 || npm run test-workspaces"
+  }
+}
diff --git a/tests/tests-workspaces/workspaces-js/js-a/index.js b/tests/tests-workspaces/workspaces-js/js-a/index.js
new file mode 100644
index 00000000..c970c823
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-js/js-a/index.js
@@ -0,0 +1,3 @@
+export function foo () {
+  return 'foo'
+}
diff --git a/tests/tests-workspaces/workspaces-js/js-a/package.json b/tests/tests-workspaces/workspaces-js/js-a/package.json
new file mode 100644
index 00000000..17e9f94a
--- /dev/null
+++ b/tests/tests-workspaces/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-workspaces/workspaces-js/js-b/esmock.js b/tests/tests-workspaces/workspaces-js/js-b/esmock.js
new file mode 100644
index 00000000..87ab45dc
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-js/js-b/esmock.js
@@ -0,0 +1,4 @@
+export * from '../../../../src/esmock.js'
+export {default} from '../../../../src/esmock.js'
+
+console.log('exportngf')
diff --git a/tests/tests-workspaces/workspaces-js/js-b/index.js b/tests/tests-workspaces/workspaces-js/js-b/index.js
new file mode 100644
index 00000000..cd6f8eba
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-js/js-b/index.js
@@ -0,0 +1,5 @@
+import {foo} from 'js-a'
+
+export default function test () {
+  return foo()
+}
diff --git a/tests/tests-workspaces/workspaces-js/js-b/package.json b/tests/tests-workspaces/workspaces-js/js-b/package.json
new file mode 100644
index 00000000..05296667
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-js/js-b/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "js-b",
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "test": "node --test"
+  },
+  "dependencies": {
+    "js-a": "^0.0.0"
+  }
+}
diff --git a/tests/tests-workspaces/workspaces-js/js-b/test.js b/tests/tests-workspaces/workspaces-js/js-b/test.js
new file mode 100644
index 00000000..94d4b7da
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-js/js-b/test.js
@@ -0,0 +1,11 @@
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import esmock from '../../../../src/esmock.js'
+
+test('works ootb', async () => {
+  const sut = await esmock('./index.js', {
+    'js-a': { foo: () => 'bar' }
+  })
+
+  assert.equal(sut(), 'bar')
+})
diff --git a/tests/tests-workspaces/workspaces-ts/ts-a/index.js b/tests/tests-workspaces/workspaces-ts/ts-a/index.js
new file mode 100644
index 00000000..c970c823
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-ts/ts-a/index.js
@@ -0,0 +1,3 @@
+export function foo () {
+  return 'foo'
+}
diff --git a/tests/tests-workspaces/workspaces-ts/ts-a/package.json b/tests/tests-workspaces/workspaces-ts/ts-a/package.json
new file mode 100644
index 00000000..b197b2fc
--- /dev/null
+++ b/tests/tests-workspaces/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-workspaces/workspaces-ts/ts-b/index.ts b/tests/tests-workspaces/workspaces-ts/ts-b/index.ts
new file mode 100644
index 00000000..426e23a3
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-ts/ts-b/index.ts
@@ -0,0 +1,8 @@
+import {foo} from 'ts-a'
+import localfile from './local-file.js'
+
+export default function test () {
+  return foo()
+}
+
+export const localfilewrap = () => localfile()
diff --git a/tests/tests-workspaces/workspaces-ts/ts-b/local-file.ts b/tests/tests-workspaces/workspaces-ts/ts-b/local-file.ts
new file mode 100644
index 00000000..6fd75c5f
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-ts/ts-b/local-file.ts
@@ -0,0 +1 @@
+export default () => 'local-value'
diff --git a/tests/tests-workspaces/workspaces-ts/ts-b/package.json b/tests/tests-workspaces/workspaces-ts/ts-b/package.json
new file mode 100644
index 00000000..0ba00655
--- /dev/null
+++ b/tests/tests-workspaces/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-workspaces/workspaces-ts/ts-b/test.ts b/tests/tests-workspaces/workspaces-ts/ts-b/test.ts
new file mode 100644
index 00000000..6eb6f968
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-ts/ts-b/test.ts
@@ -0,0 +1,19 @@
+import test from 'node:test'
+import assert from 'node:assert/strict'
+import esmock from '../../../../src/esmock.js'
+
+test('works ootb', async () => {
+  const sut = await esmock('./index.js', {
+    'ts-a': { foo: () => 'bar' }
+  })
+
+  assert.equal(sut(), 'bar')
+})
+
+test('also mocks local file', async () => {
+  const { localfilewrap } = await esmock('./index.js', {
+    './local-file.js': () => 'local-value-mocked'
+  })
+
+  assert.equal(localfilewrap(), 'local-value-mocked')
+})
diff --git a/tests/tests-workspaces/workspaces-ts/tsconfig.json b/tests/tests-workspaces/workspaces-ts/tsconfig.json
new file mode 100644
index 00000000..5b17f4eb
--- /dev/null
+++ b/tests/tests-workspaces/workspaces-ts/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "esm": true,
+  "compilerOptions": {
+    "allowSyntheticDefaultImports": true,
+    "module": "ESNext",
+    "moduleResolution": "node"
+  }
+}