Make sure it's compatible with tough-cookie@4.0.0

package.json

@@ -66,7 +66,7 @@
 		"@types/node-fetch": "^2.5.5",
 		"@types/request": "^2.48.4",
 		"@types/sinon": "^9.0.0",
-		"@types/tough-cookie": "^2.3.5",
+		"@types/tough-cookie": "^4.0.0",
 		"@typescript-eslint/eslint-plugin": "^2.27.0",
 		"@typescript-eslint/parser": "^2.27.0",
 		"ava": "^3.6.0",
@@ -89,7 +89,7 @@
 		"slow-stream": "0.0.4",
 		"tempy": "^0.5.0",
 		"to-readable-stream": "^2.1.0",
-		"tough-cookie": "^3.0.0",
+		"tough-cookie": "^4.0.0",
 		"typescript": "3.7.5",
 		"xo": "^0.29.0"
 	},

source/core/index.ts

@@ -720,14 +720,13 @@ export default class Request extends Duplex implements RequestEvents<Request> {
 		if (options.cookieJar) {
 			let {setCookie, getCookieString} = options.cookieJar;
 
-			// Horrible `tough-cookie` check
+			assert.function_(setCookie);
+			assert.function_(getCookieString);
+
+			/* istanbul ignore next: Horrible `tough-cookie` v3 check */
 			if (setCookie.length === 4 && getCookieString.length === 0) {
 				setCookie = promisify(setCookie.bind(options.cookieJar));
 				getCookieString = promisify(getCookieString.bind(options.cookieJar));
-			} else if (setCookie.length !== 2) {
-				throw new TypeError('`options.cookieJar.setCookie` needs to be an async function with 2 arguments');
-			} else if (getCookieString.length !== 1) {
-				throw new TypeError('`options.cookieJar.getCookieString` needs to be an async function with 1 argument');
 			}
 
 			options.cookieJar = {setCookie, getCookieString};

test/cookies.ts

@@ -178,19 +178,19 @@ test('throws on invalid `options.cookieJar.setCookie`', async t => {
 	// @ts-ignore Error tests
 	await t.throwsAsync(got('https://example.com', {
 		cookieJar: {
-			setCookie: () => {}
+			setCookie: 123
 		}
-	}), {message: '`options.cookieJar.setCookie` needs to be an async function with 2 arguments'});
+	}), {message: 'Expected value which is `Function`, received value of type `number`.'});
 });
 
 test('throws on invalid `options.cookieJar.getCookieString`', async t => {
 	// @ts-ignore Error tests
 	await t.throwsAsync(got('https://example.com', {
 		cookieJar: {
-			setCookie: async (_rawCookie: string, _url: string) => {},
-			getCookieString: () => {}
+			setCookie: async () => {},
+			getCookieString: 123
 		}
-	}), {message: '`options.cookieJar.getCookieString` needs to be an async function with 1 argument'});
+	}), {message: 'Expected value which is `Function`, received value of type `number`.'});
 });
 
 test('cookies are cleared when redirecting to a different hostname (no cookieJar)', withServer, async (t, server, got) => {