BREAKING CHANGE: chore(node): migrate to full esm (#338)

Author: gjuchault

.eslintrc.json

@@ -6,7 +6,7 @@
   },
   "parser": "@typescript-eslint/parser",
   "parserOptions": {
-    "project": "./tsconfig.lint.json"
+    "project": "./tsconfig.json"
   },
   "plugins": ["import", "@typescript-eslint"],
   "ignorePatterns": ["scripts/*"],

README.md

@@ -34,15 +34,15 @@ Typescript Library Starter relies on [volta](https://volta.sh/) to ensure node v
 ### Typescript
 
 Leverages [esbuild](https://github.com/evanw/esbuild) for blazing fast builds, but keeps `tsc` to generate `.d.ts` files.
-Generates two builds to support both ESM and CJS.
+Generates a single ESM build.
 
 Commands:
 
-- `build`: runs typechecking then generates CJS, ESM and `d.ts` files in the `build/` directory
+- `build`: runs typechecking then ESM and `d.ts` files in the `build/` directory
 - `clean`: removes the `build/` directory
 - `type:dts`: only generates `d.ts`
 - `type:check`: only run typechecking
-- `type:build`: only generates CJS and ESM
+- `type:build`: only generates ESM
 
 ### Tests
 

package.json

@@ -12,8 +12,8 @@
   "bugs": "https://github.com/gjuchault/typescript-library-starter/issues",
   "author": "Gabriel Juchault <[email protected]>",
   "repository": "gjuchault/typescript-library-starter",
-  "main": "./build/cjs/index.js",
-  "module": "./build/esm/index.js",
+  "type": "module",
+  "exports": "./build/index.js",
   "types": "./build/src/index.d.ts",
   "license": "MIT",
   "engines": {
@@ -32,7 +32,7 @@
     "build": "npm run clean && npm run type:dts && npm run build:main",
     "build:main": "tsx ./scripts/build",
     "clean": "tsx ./scripts/clean",
-    "type:dts": "tsc --emitDeclarationOnly",
+    "type:dts": "tsc --emitDeclarationOnly --project tsconfig.build.json",
     "type:check": "tsc --noEmit",
     "format": "prettier \"src/**/*.ts\" --write",
     "format:check": "prettier \"src/**/*.ts\" --check",

scripts/build.ts

@@ -1,10 +1,13 @@
-import path from "path";
+import path from "node:path";
+import url from "node:url";
 import { build as esbuild, BuildOptions } from "esbuild";
 
+const __dirname = url.fileURLToPath(new URL(".", import.meta.url));
+
 const baseConfig: BuildOptions = {
   platform: "node",
-  target: "esnext",
-  format: "cjs",
+  target: "node18",
+  format: "esm",
   nodePaths: [path.join(__dirname, "../src")],
   sourcemap: true,
   external: [],
@@ -14,18 +17,13 @@ const baseConfig: BuildOptions = {
 async function main() {
   await esbuild({
     ...baseConfig,
-    outdir: path.join(__dirname, "../build/cjs"),
-    entryPoints: [path.join(__dirname, "../src/index.ts")],
-  });
-
-  await esbuild({
-    ...baseConfig,
-    format: "esm",
-    outdir: path.join(__dirname, "../build/esm"),
+    outdir: path.join(__dirname, "../build"),
     entryPoints: [path.join(__dirname, "../src/index.ts")],
   });
 }
 
-if (require.main === module) {
-  main();
+if (import.meta.url.startsWith("file:")) {
+  if (process.argv[1] === url.fileURLToPath(import.meta.url)) {
+    await main();
+  }
 }

scripts/clean.ts

@@ -1,5 +1,8 @@
-import fs from "fs/promises";
-import path from "path";
+import fs from "node:fs/promises";
+import url from "node:url";
+import path from "node:path";
+
+const __dirname = url.fileURLToPath(new URL(".", import.meta.url));
 
 async function main() {
   await Promise.all([rmrf("build"), rmrf("coverage"), rmrf(".nyc_output")]);
@@ -12,6 +15,8 @@ async function rmrf(pathFromRoot: string): Promise<void> {
   });
 }
 
-if (require.main === module) {
-  main();
+if (import.meta.url.startsWith("file:")) {
+  if (process.argv[1] === url.fileURLToPath(import.meta.url)) {
+    await main();
+  }
 }

scripts/setup.ts

@@ -1,11 +1,14 @@
-import path from "path";
+import path from "node:path";
+import fs from "node:fs/promises";
+import childProcess from "node:child_process";
+import { promisify } from "node:util";
+import url from "node:url";
 import slugify from "slugify";
-import fs from "fs/promises";
-import childProcess from "child_process";
-import { promisify } from "util";
 import prompts from "prompts";
 
 const exec = promisify(childProcess.exec);
+const __filename = url.fileURLToPath(import.meta.url);
+const __dirname = url.fileURLToPath(new URL(".", import.meta.url));
 
 const rootPath = path.join(__dirname, "..");
 const releaseRcPath = path.join(rootPath, ".releaserc.json");
@@ -231,6 +234,8 @@ async function logAsyncTask<TResolve>(
   return output;
 }
 
-if (require.main === module) {
-  main();
+if (import.meta.url.startsWith("file:")) {
+  if (process.argv[1] === url.fileURLToPath(import.meta.url)) {
+    await main();
+  }
 }

scripts/testSetup.ts

@@ -1,5 +1,6 @@
-import childProcess from "child_process";
-import { promisify } from "util";
+import childProcess from "node:child_process";
+import { promisify } from "node:util";
+import url from "node:url";
 import { run } from "./setup";
 
 const exec = promisify(childProcess.exec);
@@ -60,6 +61,8 @@ async function testNoGrep(pattern: string) {
   }
 }
 
-if (require.main === module) {
-  main();
+if (import.meta.url.startsWith("file:")) {
+  if (process.argv[1] === url.fileURLToPath(import.meta.url)) {
+    await main();
+  }
 }

src/__tests__/index.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from "vitest";
-import { foobar } from "../index";
+import { foobar } from "../index.js";
 
 describe("foobar()", () => {
   describe("given two positive integers", () => {

src/index.ts

@@ -1,5 +1,5 @@
-import { bar } from "./bar";
-import { foo } from "./foo";
+import { bar } from "./bar.js";
+import { foo } from "./foo.js";
 
 export function foobar(a: number, b: number) {
   return foo().repeat(a).length + bar().repeat(b).length;

tsconfig.lint.json tsconfig.build.jsontsconfig.lint.json renamed to tsconfig.build.json

@@ -1,4 +1,4 @@
 {
   "extends": "./tsconfig.json",
-  "exclude": []
+  "exclude": ["./src/**/__tests__"]
 }