Publish native ESM alongside CommonJS

.github/workflows/ci.js.yml

@@ -39,3 +39,4 @@ jobs:
         cache-dependency-path: "typescript/package-lock.json"
     - run: npm ci
     - run: npm run build-all
+    - run: npm test

typescript/README.md

@@ -24,6 +24,30 @@ Install TypeChat:
 npm install typechat
 ```
 
+TypeChat supports both native ECMAScript modules (ESM) and CommonJS. Use `import`
+in an ESM application:
+
+```js
+import { createJsonTranslator } from "typechat";
+import { createTypeScriptJsonValidator } from "typechat/ts";
+```
+
+Or use `require` in a CommonJS application:
+
+```js
+const { createJsonTranslator } = require("typechat");
+const { createTypeScriptJsonValidator } = require("typechat/ts");
+```
+
+The `typechat`, `typechat/ts`, `typechat/zod`, and `typechat/interactive` entry points
+select the matching JavaScript build and TypeScript declarations automatically.
+Both builds target ES2021 and require Node.js 22.19.0 or newer.
+
+For compatibility with earlier CommonJS-only releases, native ESM default imports
+(`import typechat from "typechat"`) and dynamic imports' `.default` properties remain
+supported for all four entry points. Default imports also preserve the exported
+TypeScript types, such as `typechat.Result<T>`.
+
 You can also build TypeChat from source:
 
 ```sh
@@ -33,8 +57,14 @@ npm install
 npm run build
 ```
 
-Run the test suite with `npm test`. The Zod schema tests also compile their generated
-TypeScript schema text to check for syntax errors and unresolved type references.
+The build emits CommonJS JavaScript and declarations in `dist`, and native ESM
+JavaScript and declarations in `dist/esm`.
+
+Run the test suite with `npm test`. Package tests verify named and default imports,
+both module formats, and their declaration resolution using only the files included
+in the npm package.
+The Zod schema tests also compile their generated TypeScript schema text to check
+for syntax errors and unresolved type references.
 
 To see TypeChat in action, we recommend exploring the [TypeChat example projects](https://github.com/microsoft/TypeChat/tree/main/typescript/examples). You can try them on your local machine or in a GitHub Codespace.
 

typescript/package.json

@@ -20,22 +20,66 @@
     "url": "https://github.com/microsoft/TypeChat/issues"
   },
   "scripts": {
-    "build": "tsc -p src",
-    "test": "npm run build && tsc -p test && node --test out/validate.test.js out/zod.test.js out/program.test.js tests/model.test.mjs tests/examples.test.mjs",
-    "build-all": "npm run build --workspaces",
+    "build": "npm run build:cjs && npm run build:esm",
+    "build:cjs": "tsc -p src",
+    "build:esm": "tsc -p src/tsconfig.esm.json && node -e \"require('fs').writeFileSync('dist/esm/package.json', JSON.stringify({ type: 'module' }))\"",
+    "test": "npm run build && tsc -p test && node --test out/validate.test.js out/zod.test.js out/program.test.js tests/model.test.mjs tests/examples.test.mjs tests/package.test.mjs",
+    "build-all": "npm run build && npm run build --workspaces",
     "prepare": "npm run build-all",
     "prepublishOnly": "node -e \"require('fs').copyFileSync('../SECURITY.md','SECURITY.md')\"",
     "postpublish": "node -e \"require('fs').unlinkSync('SECURITY.md')\"",
     "publish-package": "npm publish",
     "publish-package:dry-run": "npm publish --dry-run"
   },
+  "type": "commonjs",
   "main": "./dist/index.js",
+  "module": "./dist/esm/index.mjs",
   "types": "./dist/index.d.ts",
   "exports": {
-    ".": "./dist/index.js",
-    "./ts": "./dist/ts/index.js",
-    "./zod": "./dist/zod/index.js",
-    "./interactive": "./dist/interactive/index.js"
+    ".": {
+      "import": {
+        "types": "./dist/esm/index.d.mts",
+        "default": "./dist/esm/index.mjs"
+      },
+      "require": {
+        "types": "./dist/index.d.ts",
+        "default": "./dist/index.js"
+      },
+      "default": "./dist/index.js"
+    },
+    "./ts": {
+      "import": {
+        "types": "./dist/esm/ts/index.d.mts",
+        "default": "./dist/esm/ts/index.mjs"
+      },
+      "require": {
+        "types": "./dist/ts/index.d.ts",
+        "default": "./dist/ts/index.js"
+      },
+      "default": "./dist/ts/index.js"
+    },
+    "./zod": {
+      "import": {
+        "types": "./dist/esm/zod/index.d.mts",
+        "default": "./dist/esm/zod/index.mjs"
+      },
+      "require": {
+        "types": "./dist/zod/index.d.ts",
+        "default": "./dist/zod/index.js"
+      },
+      "default": "./dist/zod/index.js"
+    },
+    "./interactive": {
+      "import": {
+        "types": "./dist/esm/interactive/index.d.mts",
+        "default": "./dist/esm/interactive/index.mjs"
+      },
+      "require": {
+        "types": "./dist/interactive/index.d.ts",
+        "default": "./dist/interactive/index.js"
+      },
+      "default": "./dist/interactive/index.js"
+    }
   },
   "engines": {
     "node": ">=22.19.0"

typescript/src/index.mts

@@ -0,0 +1,2 @@
+export * from './index.js';
+export * as default from './index.js';

typescript/src/index.ts

@@ -1,3 +1,3 @@
-export * from './result';
-export * from './model';
-export * from './typechat';
+export * from './result.js';
+export * from './model.js';
+export * from './typechat.js';

typescript/src/interactive/index.mts

@@ -0,0 +1,2 @@
+export * from './index.js';
+export * as default from './index.js';

typescript/src/interactive/index.ts

@@ -1 +1 @@
-export * from './interactive';
+export * from './interactive.js';

typescript/src/model.ts

@@ -1,4 +1,4 @@
-import { Result, success, error } from "./result";
+import { Result, success, error } from "./result.js";
 
 /**
  * Represents a section of an LLM prompt with an associated role. TypeChat uses the "user" role for

typescript/src/ts/index.mts

@@ -0,0 +1,2 @@
+export * from './index.js';
+export * as default from './index.js';

typescript/src/ts/index.ts

@@ -1,2 +1,2 @@
-export * from './validate';
-export * from './program';
+export * from './validate.js';
+export * from './program.js';

typescript/src/ts/program.ts

@@ -1,7 +1,7 @@
-import { Result, error, success } from "../result";
-import { TypeChatLanguageModel } from "../model";
-import { createTypeScriptJsonValidator } from "./validate";
-import { TypeChatJsonTranslator, createJsonTranslator } from "../typechat";
+import { Result, error, success } from "../result.js";
+import { TypeChatLanguageModel } from "../model.js";
+import { createTypeScriptJsonValidator } from "./validate.js";
+import { TypeChatJsonTranslator, createJsonTranslator } from "../typechat.js";
 
 const programSchemaText = `// A program consists of a sequence of function calls that are evaluated in order.
 export type Program = {

typescript/src/ts/validate.ts

@@ -1,23 +1,10 @@
-import { createRequire } from 'node:module';
-import { Result, success, error } from '../result';
-import { TypeChatJsonValidator } from "../typechat";
-
-// TypeScript 7 ships as an ES module, while this package is emitted as CommonJS. Node's
-// `require(esm)` support (Node >=22.12) lets us load it synchronously, and `resolution-mode`
-// makes the TypeScript compiler resolve the ESM-only types from a CommonJS file.
 // TODO: Revisit these `typescript/unstable/*` imports once a stable API is available.
-type SyncModule = typeof import('typescript/unstable/sync', { with: { 'resolution-mode': 'import' } });
-type FileSystemModule = typeof import('typescript/unstable/fs', { with: { 'resolution-mode': 'import' } });
-type AstIsModule = typeof import('typescript/unstable/ast/is', { with: { 'resolution-mode': 'import' } });
-
-type Checker = InstanceType<SyncModule['Checker']>;
-type Diagnostic = import('typescript/unstable/sync', { with: { 'resolution-mode': 'import' } }).Diagnostic;
-type SourceFile = import('typescript/unstable/ast', { with: { 'resolution-mode': 'import' } }).SourceFile;
-
-const requireEsm = createRequire(__filename);
-const { API, NodeBuilderFlags, SymbolFlags }: SyncModule = requireEsm('typescript/unstable/sync');
-const { createVirtualFileSystem }: FileSystemModule = requireEsm('typescript/unstable/fs');
-const { isTypeReferenceNode, isVariableStatement }: AstIsModule = requireEsm('typescript/unstable/ast/is');
+import { API, NodeBuilderFlags, SymbolFlags, type Checker, type Diagnostic } from 'typescript/unstable/sync';
+import { createVirtualFileSystem } from 'typescript/unstable/fs';
+import type { SourceFile } from 'typescript/unstable/ast';
+import { isTypeReferenceNode, isVariableStatement } from 'typescript/unstable/ast/is';
+import { Result, success, error } from '../result.js';
+import { TypeChatJsonValidator } from "../typechat.js";
 
 const libText = `interface Array<T> { length: number, [n: number]: T }
 interface Object { toString(): string }

typescript/src/tsconfig.esm.json

@@ -0,0 +1,9 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "module": "es2022",
+    "moduleResolution": "bundler",
+    "outDir": "../dist/esm"
+  },
+  "include": ["./**/*.ts", "./**/*.mts"]
+}

typescript/src/tsconfig.json

@@ -2,13 +2,14 @@
   "compilerOptions": {
     "target": "es2021",
     "lib": ["es2021"],
-    "module": "node16",
+    "module": "node20",
     "types": ["node"],
     "esModuleInterop": true,
     "outDir": "../dist",
     "skipLibCheck": true,
     "strict": true,
     "exactOptionalPropertyTypes": true,
     "declaration": true
-  }
+  },
+  "include": ["./**/*.ts"]
 }

typescript/src/typechat.ts

@@ -1,5 +1,5 @@
-import { Result, success, error } from "./result";
-import { TypeChatLanguageModel, PromptSection, PromptContent } from "./model";
+import { Result, success, error } from "./result.js";
+import { TypeChatLanguageModel, PromptSection, PromptContent } from "./model.js";
 
 /**
  * Represents an object that can translate natural language requests in JSON objects of the given type.

typescript/src/zod/index.mts

@@ -0,0 +1,2 @@
+export * from './index.js';
+export * as default from './index.js';

typescript/src/zod/index.ts

@@ -1 +1 @@
-export * from './validate';
+export * from './validate.js';

typescript/src/zod/validate.ts

@@ -1,6 +1,6 @@
 import { z } from "zod";
-import { success, error } from '../result';
-import { TypeChatJsonValidator } from '../typechat';
+import { success, error } from '../result.js';
+import { TypeChatJsonValidator } from '../typechat.js';
 
 /**
  * Returns a JSON validator for a given Zod schema. The schema is supplied as an object where each property provides