Sample code for 30+ languages & platforms
JavaScript

Check Whether a Socket Is Writable

See more Socket/SSL/TLS Examples

Demonstrates Socket.CheckWriteable, which waits for the connected socket to become writable. It returns 1 if writable, 0 if it did not become writable before the timeout, or -1 on error.

Background. A maxWaitMs of 0 performs a nonblocking poll. This is useful for flow control before attempting a large send.
Note
This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.
JavaScript
var success = false;

var socket = new CkSocket();

//  Connect to the server using TLS.
var bTls = true;
var maxWaitMs = 5000;
success = socket.Connect("example.com",5000,bTls,maxWaitMs);
if (success == false) {
    console.log(socket.LastErrorText);
    return;
}

//  Wait up to 5 seconds for the socket to become writable.  Returns 1 if writable, 0 if it did not
//  become writable before the timeout, or -1 on error.
var writable = socket.CheckWriteable(5000);
if (writable < 0) {
    console.log(socket.LastErrorText);
    return;
}

if (writable !== 1) {
    console.log("The socket did not become writable before the timeout.");
    return;
}

console.log("The socket is writable.");