Remove https core module patching logic

Instead of patching over `https.request()` and `https.get()` manually
to add the `secureEndpoint` boolean, utilize the stack trace of the
current call logic to determine whether or not the `https.js` core
module is invoking `new ClientRequest()`.

In theory, this is still fragile logic, but should be more future-proof
and cleaner than patching over a core module, which is never really
desirable.

Fixes #29.
Closes #30.
Closes #35.

.gitignore

@@ -1,5 +1,5 @@
 /package-lock.json
 /yarn.lock
 /node_modules
-/?.js
+/?.?s
 /dist

src/index.ts

@@ -1,4 +1,3 @@
-import './patch-core';
 import net from 'net';
 import http from 'http';
 import promisify from 'es6-promisify';
@@ -12,6 +11,12 @@ function isHttpAgent(v: any): v is http.Agent {
 	return Boolean(v) && typeof v.addRequest === 'function';
 }
 
+function isSecureEndpoint(): boolean {
+	const { stack } = new Error();
+	if (typeof stack !== 'string') return false;
+	return stack.split('\n').some(l => l.indexOf('(https.js:') !== -1);
+}
+
 function createAgent(opts?: createAgent.AgentOptions): createAgent.Agent;
 function createAgent(
 	callback: createAgent.AgentCallback,
@@ -105,6 +110,10 @@ namespace createAgent {
 			this.requests = [];
 		}
 
+		get defaultPort(): number {
+			return isSecureEndpoint() ? 443 : 80;
+		}
+
 		callback(
 			req: createAgent.ClientRequest,
 			opts: createAgent.RequestOptions,
@@ -136,7 +145,10 @@ namespace createAgent {
 		 * @api public
 		 */
 		addRequest(req: ClientRequest, _opts: RequestOptions) {
-			const ownOpts: RequestOptions = { ..._opts };
+			const ownOpts: RequestOptions = {
+				..._opts,
+				secureEndpoint: isSecureEndpoint()
+			};
 
 			// Set default `host` for HTTP to localhost
 			if (ownOpts.host == null) {

test/test-legacy.js

@@ -572,17 +572,6 @@ describe('"https" module', function() {
 		});
 	});
 
-	it('should not re-patch https.request', () => {
-		var patchModulePath = '../src/patch-core';
-		var patchedRequest = https.request;
-
-		delete require.cache[require.resolve(patchModulePath)];
-		require(patchModulePath);
-
-		assert.equal(patchedRequest, https.request);
-		assert.equal(true, https.request.__agent_base_https_request_patched__);
-	});
-
 	describe('PassthroughAgent', function() {
 		it('should pass through to `https.globalAgent`', function(done) {
 			// add HTTP server "request" listener