Follow enableKeepAlive option

lib/connection.js

@@ -37,9 +37,11 @@ class Connection extends EventEmitter {
           opts.config.host
         );
 
-        // Enable keep-alive on the socket.  It's disabled by default, but the
-        // user can enable it and supply an initial delay.
-        this.stream.setKeepAlive(true, this.config.keepAliveInitialDelay);
+        // Enable keep-alive on the socket.
+        // It's enabled by default and user can supply an initial delay.
+        if (this.config.enableKeepAlive) {
+          this.stream.setKeepAlive(true, this.config.keepAliveInitialDelay);
+        }
       }
       // if stream is a function, treat it as "stream agent / factory"
     } else if (typeof opts.config.stream === 'function')  {

lib/connection_config.js

@@ -95,7 +95,8 @@ class ConnectionConfig {
     this.debug = options.debug;
     this.trace = options.trace !== false;
     this.stringifyObjects = options.stringifyObjects || false;
-    this.enableKeepAlive = !!options.enableKeepAlive;
+    this.enableKeepAlive =
+      options.enableKeepAlive === undefined || options.enableKeepAlive;
     this.keepAliveInitialDelay = options.keepAliveInitialDelay || 0;
     if (
       options.timezone &&

typings/mysql/lib/Pool.d.ts

@@ -33,8 +33,7 @@ declare namespace Pool {
         queueLimit?: number;
 
         /**
-         * Enable keep-alive on the socket.  It's disabled by default, but the
-         * user can enable it and supply an initial delay.
+         * Enable keep-alive on the socket. It's enabled by default.
          */
         enableKeepAlive?: true;