Require Node.js 12.20.0 and move to ESM

.github/FUNDING.yml

@@ -1,6 +1,6 @@
 # These are supported funding model platforms
 
-github: # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
+github: node-fetch # Replace with up to 4 GitHub Sponsors-enabled usernames e.g., [user1, user2]
 patreon: # Replace with a single Patreon username
 open_collective: node-fetch # Replace with a single Open Collective username
 ko_fi: # Replace with a single Ko-fi username

.github/workflows/ci.yml

@@ -14,52 +14,27 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, windows-latest, macOS-latest]
-        node: ["14", "12", engines]
+        node: ["12.22.3", "14.13.1", "16.0.0"]
         exclude:
           # On Windows, run tests with only the LTS environments.
           - os: windows-latest
-            node: engines
+            node: "12.22.3"
           - os: windows-latest
-            node: "14"
+            node: "16.0.0"
           # On macOS, run tests with only the LTS environments.
           - os: macOS-latest
-            node: engines
+            node: "12.22.3"
           - os: macOS-latest
-            node: "14"
+            node: "16.0.0"
 
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2
 
-      - name: Get Node.JS version from package.json
-        if: matrix.node == 'engines'
-        id: get-version
-        run: echo ::set-output name=node::$(npx --q minimum-node-version)
-
-      - uses: actions/setup-node@v2-beta
-        if: matrix.node != 'engines'
+      - uses: actions/setup-node@v2
         with:
           node-version: ${{ matrix.node }}
 
-      - uses: actions/setup-node@v2-beta
-        if: matrix.node == 'engines'
-        with:
-          node-version: ${{steps.get-version.outputs.node}}
-
       - run: npm install
 
       - run: npm test -- --colors
-        if: matrix.node != 'engines'
-
-      - name: Test without coverage
-        if: matrix.node == 'engines'
-        run: |
-          npm i esm
-          npx mocha -r esm --colors
-
-      # upload coverage only once
-      - name: Coveralls
-        uses: coverallsapp/github-action@master
-        if: matrix.node == '12' && matrix.os == 'ubuntu-latest'
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/lint.yml

@@ -13,7 +13,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: Use Node.js
-        uses: actions/setup-node@v2-beta
+        uses: actions/setup-node@v2
         with:
           node-version: 14
       - run: npm install

.github/workflows/types.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2-beta
+      - uses: actions/setup-node@v2
 
       - run: npm install
 

.gitignore

@@ -1,9 +1,6 @@
 # Sketch temporary file
 ~*.sketch
 
-# Generated files
-dist/
-
 # Logs
 logs
 *.log

@types/index.d.ts

@@ -1,19 +1,16 @@
 /// <reference types="node" />
+/// <reference lib="dom" />
 
-/* eslint-disable no-var, import/no-mutable-exports */
-
-import { Agent } from 'http';
-import { URL, URLSearchParams } from 'url'
-import Blob = require('fetch-blob');
+import {Agent} from 'http';
 
 type AbortSignal = {
 	readonly aborted: boolean;
 
-	addEventListener(type: "abort", listener: (this: AbortSignal) => void): void;
-	removeEventListener(type: "abort", listener: (this: AbortSignal) => void): void;
+	addEventListener: (type: 'abort', listener: (this: AbortSignal) => void) => void;
+	removeEventListener: (type: 'abort', listener: (this: AbortSignal) => void) => void;
 };
 
-type HeadersInit = Headers | Record<string, string> | Iterable<readonly [string, string]> | Iterable<Iterable<string>>;
+export type HeadersInit = Headers | Record<string, string> | Iterable<readonly [string, string]> | Iterable<Iterable<string>>;
 
 /**
  * This Fetch API interface allows you to perform various actions on HTTP request and response headers.
@@ -22,7 +19,7 @@ type HeadersInit = Headers | Record<string, string> | Iterable<readonly [string,
  * You can add to this using methods like append() (see Examples.)
  * In all methods of this interface, header names are matched by case-insensitive byte sequence.
  * */
-declare class Headers {
+export class Headers {
 	constructor(init?: HeadersInit);
 
 	append(name: string, value: string): void;
@@ -53,7 +50,7 @@ declare class Headers {
 	raw(): Record<string, string[]>;
 }
 
-interface RequestInit {
+export interface RequestInit {
 	/**
 	 * A BodyInit object or null to set request's body.
 	 */
@@ -88,21 +85,20 @@ interface RequestInit {
 	insecureHTTPParser?: boolean;
 }
 
-interface ResponseInit {
+export interface ResponseInit {
 	headers?: HeadersInit;
 	status?: number;
 	statusText?: string;
 }
 
-type BodyInit =
+export type BodyInit =
 	| Blob
 	| Buffer
 	| URLSearchParams
 	| NodeJS.ReadableStream
 	| string;
-type BodyType = { [K in keyof Body]: Body[K] };
-declare class Body {
-	constructor(body?: BodyInit, opts?: { size?: number });
+declare class BodyMixin {
+	constructor(body?: BodyInit, options?: {size?: number});
 
 	readonly body: NodeJS.ReadableStream | null;
 	readonly bodyUsed: boolean;
@@ -115,9 +111,12 @@ declare class Body {
 	text(): Promise<string>;
 }
 
-type RequestRedirect = 'error' | 'follow' | 'manual';
-type RequestInfo = string | Body;
-declare class Request extends Body {
+// `Body` must not be exported as a class since it's not exported from the JavaScript code.
+export interface Body extends Pick<BodyMixin, keyof BodyMixin> {}
+
+export type RequestRedirect = 'error' | 'follow' | 'manual';
+export type RequestInfo = string | Request;
+export class Request extends BodyMixin {
 	constructor(input: RequestInfo, init?: RequestInit);
 
 	/**
@@ -143,9 +142,9 @@ declare class Request extends Body {
 	clone(): Request;
 }
 
-type ResponseType = "basic" | "cors" | "default" | "error" | "opaque" | "opaqueredirect"
+type ResponseType = 'basic' | 'cors' | 'default' | 'error' | 'opaque' | 'opaqueredirect';
 
-declare class Response extends Body {
+export class Response extends BodyMixin {
 	constructor(body?: BodyInit | null, init?: ResponseInit);
 
 	readonly headers: Headers;
@@ -160,8 +159,8 @@ declare class Response extends Body {
 	static error(): Response;
 }
 
-declare class FetchError extends Error {
-	constructor(message: string, type: string, systemError?: object);
+export class FetchError extends Error {
+	constructor(message: string, type: string, systemError?: Record<string, unknown>);
 
 	name: 'FetchError';
 	[Symbol.toStringTag]: 'FetchError';
@@ -170,39 +169,11 @@ declare class FetchError extends Error {
 	errno?: string;
 }
 
-declare class AbortError extends Error {
+export class AbortError extends Error {
 	type: string;
 	name: 'AbortError';
 	[Symbol.toStringTag]: 'AbortError';
 }
 
-
-declare function fetch(url: RequestInfo, init?: RequestInit): Promise<Response>;
-declare class fetch {
-	static default: typeof fetch;
-}
-declare namespace fetch {
-	export function isRedirect(code: number): boolean;
-
-	export {
-		HeadersInit,
-		Headers,
-
-		RequestInit,
-		RequestRedirect,
-		RequestInfo,
-		Request,
-
-		BodyInit,
-
-		ResponseInit,
-		Response,
-
-		FetchError,
-		AbortError
-	};
-
-	export interface Body extends BodyType { }
-}
-
-export = fetch;
+export function isRedirect(code: number): boolean;
+export default function fetch(url: RequestInfo, init?: RequestInit): Promise<Response>;