Convert all packages to ESM with type: module

TooTallNate · TooTallNate · commit 9c92c09649db · 2026-03-06T14:06:55.000-08:00
BREAKING CHANGE: All packages now use `"type": "module"` and emit
ESM output instead of CommonJS. The tsconfig base has been updated
to use `module: NodeNext` and `moduleResolution: NodeNext`.

Changes include:
- Add `"type": "module"` to all publishable package.json files
- Replace `main`/`types` with proper `exports` fields
- Update tsconfig base to NodeNext module/moduleResolution
- Add .js extensions to all relative imports (required by NodeNext)
- Fix CommonJS-specific code in proxy package (require -&gt; createRequire)
- Align get-uri tsconfig to extend shared base
- Add changeset for semver major bump on all packages
diff --git a/.changeset/esm-migration.md b/.changeset/esm-migration.md
@@ -0,0 +1,15 @@
+---
+"agent-base": major
+"http-proxy-agent": major
+"https-proxy-agent": major
+"proxy-agent": major
+"socks-proxy-agent": major
+"pac-proxy-agent": major
+"pac-resolver": major
+"degenerator": major
+"get-uri": major
+"data-uri-to-buffer": major
+"proxy": major
+---
+
+Convert to ESM. All packages now use `"type": "module"` and compile to ESM output instead of CommonJS.
diff --git a/packages/agent-base/package.json b/packages/agent-base/package.json
@@ -1,9 +1,14 @@
 {
   "name": "agent-base",
   "version": "7.1.4",
+  "type": "module",
   "description": "Turn a function into an `http.Agent` instance",
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
+  "exports": {
+    "import": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
+  },
   "files": [
     "dist"
   ],
diff --git a/packages/agent-base/src/index.ts b/packages/agent-base/src/index.ts
@@ -4,7 +4,7 @@ import * as http from 'http';
 import { Agent as HttpsAgent } from 'https';
 import type { Duplex } from 'stream';
 
-export * from './helpers';
+export * from './helpers.js';
 
 interface HttpConnectOpts extends net.TcpNetConnectOpts {
 	secureEndpoint: false;
diff --git a/packages/data-uri-to-buffer/package.json b/packages/data-uri-to-buffer/package.json
@@ -1,12 +1,17 @@
 {
   "name": "data-uri-to-buffer",
   "version": "6.0.2",
+  "type": "module",
   "description": "Create an ArrayBuffer instance from a Data URI string",
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
   "exports": {
-    "node": "./dist/node.js",
-    "default": "./dist/index.js"
+    "node": {
+      "types": "./dist/node.d.ts",
+      "default": "./dist/node.js"
+    },
+    "default": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
   },
   "files": [
     "dist"
diff --git a/packages/data-uri-to-buffer/src/index.ts b/packages/data-uri-to-buffer/src/index.ts
@@ -1,6 +1,6 @@
-import { makeDataUriToBuffer } from './common';
+import { makeDataUriToBuffer } from './common.js';
 
-export type { ParsedDataURI } from './common';
+export type { ParsedDataURI } from './common.js';
 
 function base64ToArrayBuffer(base64: string) {
 	const chars =
diff --git a/packages/data-uri-to-buffer/src/node.ts b/packages/data-uri-to-buffer/src/node.ts
@@ -1,6 +1,6 @@
-import { makeDataUriToBuffer } from './common';
+import { makeDataUriToBuffer } from './common.js';
 
-export type { ParsedDataURI } from './common';
+export type { ParsedDataURI } from './common.js';
 
 function nodeBuffertoArrayBuffer(nodeBuf: Buffer): ArrayBuffer {
 	if (nodeBuf.byteLength === nodeBuf.buffer.byteLength) {
diff --git a/packages/degenerator/package.json b/packages/degenerator/package.json
@@ -1,9 +1,14 @@
 {
   "name": "degenerator",
   "version": "5.0.1",
+  "type": "module",
   "description": "Compiles sync functions into async generator functions",
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
+  "exports": {
+    "import": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
+  },
   "files": [
     "dist"
   ],
diff --git a/packages/degenerator/src/compile.ts b/packages/degenerator/src/compile.ts
@@ -1,12 +1,12 @@
 import { types } from 'util';
-import { degenerator } from './degenerator';
+import { degenerator } from './degenerator.js';
 import type { Context } from 'vm';
 import type {
 	QuickJSContext,
 	QuickJSHandle,
 	QuickJSWASMModule,
 } from '@tootallnate/quickjs-emscripten';
-import type { DegeneratorNames } from './degenerator';
+import type { DegeneratorNames } from './degenerator.js';
 
 export interface CompileOptions {
 	names?: DegeneratorNames;
diff --git a/packages/degenerator/src/index.ts b/packages/degenerator/src/index.ts
@@ -1,2 +1,2 @@
-export * from './degenerator';
-export * from './compile';
+export * from './degenerator.js';
+export * from './compile.js';
diff --git a/packages/get-uri/package.json b/packages/get-uri/package.json
@@ -1,9 +1,14 @@
 {
   "name": "get-uri",
   "version": "6.0.5",
+  "type": "module",
   "description": "Returns a `stream.Readable` from a URI string",
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
+  "exports": {
+    "import": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
+  },
   "files": [
     "dist"
   ],
diff --git a/packages/get-uri/src/data.ts b/packages/get-uri/src/data.ts
@@ -2,8 +2,8 @@ import createDebug from 'debug';
 import { Readable } from 'stream';
 import { createHash } from 'crypto';
 import { dataUriToBuffer } from 'data-uri-to-buffer';
-import { GetUriProtocol } from './';
-import NotModifiedError from './notmodified';
+import { GetUriProtocol } from './index.js';
+import NotModifiedError from './notmodified.js';
 
 const debug = createDebug('get-uri:data');
 
diff --git a/packages/get-uri/src/file.ts b/packages/get-uri/src/file.ts
@@ -1,9 +1,9 @@
 import { Readable } from 'stream';
 import createDebug from 'debug';
 import { Stats, createReadStream, promises as fsPromises } from 'fs';
-import { GetUriProtocol } from './';
-import NotFoundError from './notfound';
-import NotModifiedError from './notmodified';
+import { GetUriProtocol } from './index.js';
+import NotFoundError from './notfound.js';
+import NotModifiedError from './notmodified.js';
 import { fileURLToPath } from 'url';
 
 const debug = createDebug('get-uri:file');
diff --git a/packages/get-uri/src/ftp.ts b/packages/get-uri/src/ftp.ts
@@ -2,9 +2,9 @@ import { Client, AccessOptions } from 'basic-ftp';
 import { PassThrough, Readable } from 'stream';
 import { basename, dirname } from 'path';
 import createDebug from 'debug';
-import NotFoundError from './notfound';
-import NotModifiedError from './notmodified';
-import { GetUriProtocol } from '.';
+import NotFoundError from './notfound.js';
+import NotModifiedError from './notmodified.js';
+import { GetUriProtocol } from './index.js';
 
 const debug = createDebug('get-uri:ftp');
 
diff --git a/packages/get-uri/src/http.ts b/packages/get-uri/src/http.ts
@@ -3,10 +3,10 @@ import https from 'https';
 import { once } from 'events';
 import { Readable } from 'stream';
 import createDebug from 'debug';
-import { GetUriProtocol } from '.';
-import HTTPError from './http-error';
-import NotFoundError from './notfound';
-import NotModifiedError from './notmodified';
+import { GetUriProtocol } from './index.js';
+import HTTPError from './http-error.js';
+import NotFoundError from './notfound.js';
+import NotModifiedError from './notmodified.js';
 
 const debug = createDebug('get-uri:http');
 
diff --git a/packages/get-uri/src/https.ts b/packages/get-uri/src/https.ts
@@ -1,6 +1,6 @@
 import https_ from 'https';
-import { http, HttpOptions } from './http';
-import type { GetUriProtocol } from '.';
+import { http, HttpOptions } from './http.js';
+import type { GetUriProtocol } from './index.js';
 
 /**
  * Returns a Readable stream from an "https:" URI.
diff --git a/packages/get-uri/src/index.ts b/packages/get-uri/src/index.ts
@@ -2,11 +2,11 @@ import createDebug from 'debug';
 import { Readable } from 'stream';
 
 // Built-in protocols
-import { data } from './data';
-import { file } from './file';
-import { ftp } from './ftp';
-import { http } from './http';
-import { https } from './https';
+import { data } from './data.js';
+import { file } from './file.js';
+import { ftp } from './ftp.js';
+import { http } from './http.js';
+import { https } from './https.js';
 
 const debug = createDebug('get-uri');
 
diff --git a/packages/get-uri/tsconfig.json b/packages/get-uri/tsconfig.json
@@ -1,15 +1,9 @@
 {
+  "extends": "tsconfig/base.json",
   "compilerOptions": {
-    "strict": true,
-    "module": "CommonJS",
-    "target": "es2020",
-    "esModuleInterop": true,
-    "lib": ["esnext"],
     "outDir": "dist",
-    "sourceMap": true,
-    "declaration": true,
     "typeRoots": ["./@types", "./node_modules/@types"]
   },
-  "include": ["src/**/*"],
+  "include": ["src"],
   "exclude": ["node_modules"]
 }
diff --git a/packages/http-proxy-agent/package.json b/packages/http-proxy-agent/package.json
@@ -1,9 +1,14 @@
 {
   "name": "http-proxy-agent",
   "version": "7.0.2",
+  "type": "module",
   "description": "An HTTP(s) proxy `http.Agent` implementation for HTTP",
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
+  "exports": {
+    "import": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
+  },
   "files": [
     "dist"
   ],
diff --git a/packages/https-proxy-agent/package.json b/packages/https-proxy-agent/package.json
@@ -1,9 +1,14 @@
 {
   "name": "https-proxy-agent",
   "version": "7.0.6",
+  "type": "module",
   "description": "An HTTP(s) proxy `http.Agent` implementation for HTTPS",
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
+  "exports": {
+    "import": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
+  },
   "files": [
     "dist"
   ],
diff --git a/packages/https-proxy-agent/src/index.ts b/packages/https-proxy-agent/src/index.ts
@@ -5,7 +5,7 @@ import assert from 'assert';
 import createDebug from 'debug';
 import { Agent, AgentConnectOpts } from 'agent-base';
 import { URL } from 'url';
-import { parseProxyResponse } from './parse-proxy-response';
+import { parseProxyResponse } from './parse-proxy-response.js';
 import type { OutgoingHttpHeaders } from 'http';
 
 const debug = createDebug('https-proxy-agent');
diff --git a/packages/pac-proxy-agent/package.json b/packages/pac-proxy-agent/package.json
@@ -1,9 +1,14 @@
 {
   "name": "pac-proxy-agent",
   "version": "7.2.0",
+  "type": "module",
   "description": "A PAC file proxy `http.Agent` implementation for HTTP",
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
+  "exports": {
+    "import": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
+  },
   "files": [
     "dist"
   ],
diff --git a/packages/pac-resolver/package.json b/packages/pac-resolver/package.json
@@ -1,9 +1,14 @@
 {
   "name": "pac-resolver",
   "version": "7.0.1",
+  "type": "module",
   "description": "Generates an asynchronous resolver function from a PAC file",
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
+  "exports": {
+    "import": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
+  },
   "files": [
     "dist"
   ],
diff --git a/packages/pac-resolver/src/dnsResolve.ts b/packages/pac-resolver/src/dnsResolve.ts
@@ -1,4 +1,4 @@
-import { dnsLookup } from './util';
+import { dnsLookup } from './util.js';
 
 /**
  * Resolves the given DNS hostname into an IP address, and returns it in the dot
diff --git a/packages/pac-resolver/src/index.ts b/packages/pac-resolver/src/index.ts
@@ -4,18 +4,18 @@ import { CompileOptions, compile } from 'degenerator';
 /**
  * Built-in PAC functions.
  */
-import dateRange from './dateRange';
-import dnsDomainIs from './dnsDomainIs';
-import dnsDomainLevels from './dnsDomainLevels';
-import dnsResolve from './dnsResolve';
-import isInNet from './isInNet';
-import isPlainHostName from './isPlainHostName';
-import isResolvable from './isResolvable';
-import localHostOrDomainIs from './localHostOrDomainIs';
-import myIpAddress from './myIpAddress';
-import shExpMatch from './shExpMatch';
-import timeRange from './timeRange';
-import weekdayRange from './weekdayRange';
+import dateRange from './dateRange.js';
+import dnsDomainIs from './dnsDomainIs.js';
+import dnsDomainLevels from './dnsDomainLevels.js';
+import dnsResolve from './dnsResolve.js';
+import isInNet from './isInNet.js';
+import isPlainHostName from './isPlainHostName.js';
+import isResolvable from './isResolvable.js';
+import localHostOrDomainIs from './localHostOrDomainIs.js';
+import myIpAddress from './myIpAddress.js';
+import shExpMatch from './shExpMatch.js';
+import timeRange from './timeRange.js';
+import weekdayRange from './weekdayRange.js';
 import type { QuickJSWASMModule } from '@tootallnate/quickjs-emscripten';
 
 /**
diff --git a/packages/pac-resolver/src/isInNet.ts b/packages/pac-resolver/src/isInNet.ts
@@ -1,5 +1,5 @@
 import { Netmask } from 'netmask';
-import { dnsLookup } from './util';
+import { dnsLookup } from './util.js';
 
 /**
  * True iff the IP address of the host matches the specified IP address pattern.
diff --git a/packages/pac-resolver/src/isResolvable.ts b/packages/pac-resolver/src/isResolvable.ts
@@ -1,4 +1,4 @@
-import { dnsLookup } from './util';
+import { dnsLookup } from './util.js';
 
 /**
  * Tries to resolve the hostname. Returns true if succeeds.
diff --git a/packages/pac-resolver/src/myIpAddress.ts b/packages/pac-resolver/src/myIpAddress.ts
@@ -1,4 +1,4 @@
-import { ip } from './ip';
+import { ip } from './ip.js';
 import net, { AddressInfo } from 'net';
 
 /**
diff --git a/packages/pac-resolver/src/util.ts b/packages/pac-resolver/src/util.ts
@@ -1,5 +1,5 @@
 import { LookupAddress, LookupOptions, lookup } from 'dns';
-import { GMT } from './index';
+import { GMT } from './index.js';
 
 export function dnsLookup(
 	host: string,
diff --git a/packages/pac-resolver/src/weekdayRange.ts b/packages/pac-resolver/src/weekdayRange.ts
@@ -1,5 +1,5 @@
-import { isGMT } from './util';
-import { GMT, Weekday } from './index';
+import { isGMT } from './util.js';
+import { GMT, Weekday } from './index.js';
 
 const weekdays: Weekday[] = ['SUN', 'MON', 'TUE', 'WED', 'THU', 'FRI', 'SAT'];
 
diff --git a/packages/proxy-agent/package.json b/packages/proxy-agent/package.json
@@ -1,9 +1,14 @@
 {
   "name": "proxy-agent",
   "version": "6.5.0",
+  "type": "module",
   "description": "Maps proxy protocols to `http.Agent` implementations",
-  "main": "./dist/index.js",
-  "types": "./dist/index.d.ts",
+  "exports": {
+    "import": {
+      "types": "./dist/index.d.ts",
+      "default": "./dist/index.js"
+    }
+  },
   "files": [
     "dist"
   ],
diff --git a/packages/proxy/package.json b/packages/proxy/package.json
diff --git a/packages/proxy/src/bin/proxy.ts b/packages/proxy/src/bin/proxy.ts
diff --git a/packages/proxy/src/pkg.ts b/packages/proxy/src/pkg.ts
diff --git a/packages/proxy/src/proxy.ts b/packages/proxy/src/proxy.ts
diff --git a/packages/socks-proxy-agent/package.json b/packages/socks-proxy-agent/package.json
diff --git a/packages/tsconfig/base.json b/packages/tsconfig/base.json
