diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/package.json b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/package.json
new file mode 100644
index 0000000..de3754d
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "117-const-enums.explainer",
+  "version": "1.0.0",
+  "description": "",
+  "scripts": {
+    "dev": "nodemon --exec \"tsc && node dist/index.mjs\" ./src/index.mts"
+  },
+  "keywords": [],
+  "author": "Matt Pocock",
+  "devDependencies": {},
+  "type": "module"
+}
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/src/esm-module.ts b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/src/esm-module.ts
new file mode 100644
index 0000000..ccea393
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/src/esm-module.ts
@@ -0,0 +1,6 @@
+const hello = () => {
+  console.log("Hello!");
+};
+
+// @ts-expect-error
+export default hello;
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/src/index.ts b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/src/index.ts
new file mode 100644
index 0000000..4264c8e
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/src/index.ts
@@ -0,0 +1,8 @@
+// @ts-expect-error
+import esModule from "./esm-module.js";
+
+const main = async () => {
+  esModule();
+};
+
+main();
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/tsconfig.json b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/tsconfig.json
new file mode 100644
index 0000000..0401340
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.problem/tsconfig.json
@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "outDir": "dist",
+    "esModuleInterop": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "isolatedModules": true,
+    "verbatimModuleSyntax": true
+  },
+}
\ No newline at end of file
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/package.json b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/package.json
new file mode 100644
index 0000000..be6394a
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/package.json
@@ -0,0 +1,11 @@
+{
+  "name": "117-const-enums.explainer",
+  "version": "1.0.0",
+  "description": "",
+  "scripts": {
+    "dev": "nodemon --exec \"tsc && node dist/index.mjs\" ./src/index.mts"
+  },
+  "keywords": [],
+  "author": "Matt Pocock",
+  "devDependencies": {}
+}
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/src/esm-module.ts b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/src/esm-module.ts
new file mode 100644
index 0000000..ccea393
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/src/esm-module.ts
@@ -0,0 +1,6 @@
+const hello = () => {
+  console.log("Hello!");
+};
+
+// @ts-expect-error
+export default hello;
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/src/index.ts b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/src/index.ts
new file mode 100644
index 0000000..4264c8e
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/src/index.ts
@@ -0,0 +1,8 @@
+// @ts-expect-error
+import esModule from "./esm-module.js";
+
+const main = async () => {
+  esModule();
+};
+
+main();
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/tsconfig.json b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/tsconfig.json
new file mode 100644
index 0000000..0401340
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.1/tsconfig.json
@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "outDir": "dist",
+    "esModuleInterop": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "isolatedModules": true,
+    "verbatimModuleSyntax": true
+  },
+}
\ No newline at end of file
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/package.json b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/package.json
new file mode 100644
index 0000000..de3754d
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/package.json
@@ -0,0 +1,12 @@
+{
+  "name": "117-const-enums.explainer",
+  "version": "1.0.0",
+  "description": "",
+  "scripts": {
+    "dev": "nodemon --exec \"tsc && node dist/index.mjs\" ./src/index.mts"
+  },
+  "keywords": [],
+  "author": "Matt Pocock",
+  "devDependencies": {},
+  "type": "module"
+}
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/src/esm-module.cts b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/src/esm-module.cts
new file mode 100644
index 0000000..ccea393
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/src/esm-module.cts
@@ -0,0 +1,6 @@
+const hello = () => {
+  console.log("Hello!");
+};
+
+// @ts-expect-error
+export default hello;
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/src/index.cts b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/src/index.cts
new file mode 100644
index 0000000..4264c8e
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/src/index.cts
@@ -0,0 +1,8 @@
+// @ts-expect-error
+import esModule from "./esm-module.js";
+
+const main = async () => {
+  esModule();
+};
+
+main();
diff --git a/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/tsconfig.json b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/tsconfig.json
new file mode 100644
index 0000000..0401340
--- /dev/null
+++ b/src/082-cjs-vs-esm/209.5-treat-ts-files-as-cjs.solution.2/tsconfig.json
@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "outDir": "dist",
+    "esModuleInterop": true,
+    "strict": true,
+    "skipLibCheck": true,
+    "isolatedModules": true,
+    "verbatimModuleSyntax": true
+  },
+}
\ No newline at end of file