change false => ''

Author: indutny

doc/api/https.md

@@ -29,9 +29,9 @@ An [`Agent`][] object for HTTPS similar to [`http.Agent`][]. See
   Can have the same fields as for [`http.Agent(options)`][], and
   * `maxCachedSessions` {number} maximum number of TLS cached sessions.
     Use `0` to disable TLS session caching. **Default:** `100`.
-  * `servername` {string | boolean} the value of
+  * `servername` {string} the value of
     [Server Name Indication extension][sni wiki] to be sent to the server. Use
-    `false` to disable sending the extension.
+    empty string `''` to disable sending the extension.
     **Default:** hostname or IP address of the target server.
 
     See [`Session Resumption`][] for infomation about TLS session reuse.

lib/_http_agent.js

@@ -151,7 +151,7 @@ Agent.prototype.addRequest = function addRequest(req, options, port/* legacy */,
   if (options.socketPath)
     options.path = options.socketPath;
 
-  if (!options.servername && options.servername !== false)
+  if (!options.servername && options.servername !== '')
     options.servername = calculateServerName(options, req);
 
   const name = this.getName(options);
@@ -198,7 +198,7 @@ Agent.prototype.createSocket = function createSocket(req, options, cb) {
   if (options.socketPath)
     options.path = options.socketPath;
 
-  if (!options.servername && options.servername !== false)
+  if (!options.servername && options.servername !== '')
     options.servername = calculateServerName(options, req);
 
   const name = this.getName(options);

test/parallel/test-https-agent-sni.js

@@ -56,7 +56,7 @@ server.listen(0, function() {
     path: '/',
     port: this.address().port,
     host: '127.0.0.1',
-    servername: false,
+    servername: '',
     rejectUnauthorized: false
   }, expectResponse(false));
 });