plz-port

plz-port
============

please give me any port if the port is opened.

``javascript
const plzPort = require('plz-port');

plzPort().then((port) => {
assert(port >= 3000); // random port range is 3000 < 65535
assert(port <= 65535);
});

plzPort(3000).then((port) => {
console.log(port); // 3000 if the port is opened.
});

plzPort(8080).then((port) => {
console.log(port); // 8081, 8082, 8083.... increment the port until found open port
});
``