hm-react-cli/webpack/utils/getUsablePort.js

Create a Huimei React project by module

const net = require('net');

const tryUsePort = async function (port, portAvailableCallback) {
    function portUsed(port) {
        return new Promise((resolve, reject) => {
            let server = net.createServer().listen(port);
            server.on('listening', function () {
                server.close();
                resolve(port);
            });
            server.on('error', function (err) {
                if (err.code == 'EADDRINUSE') {
                    resolve(err);
                }
            });
        });
    }

    let res = await portUsed(port);
    if (res instanceof Error) {
        port++;
        return tryUsePort(port, portAvailableCallback);
    } else {
        portAvailableCallback && portAvailableCallback(port);

        return Promise.resolve(port);
    }
};

// 输入一个预设的端口号，不可用在其基础 +1，直到输出一个可用的端口号
module.exports = tryUsePort;