frontity/src/utils/choosePort.ts

Frontity cli and entry point to other packages

import chalk from "chalk";
import detect from "detect-port-alt";
import isRoot from "is-root";
import inquirer from "inquirer";

import getProcessForPort from "./getProcessForPort";

const isInteractive = process.stdout.isTTY;

function clearConsole() {
  process.stdout.write(
    process.platform === "win32" ? "\x1B[2J\x1B[0f" : "\x1B[2J\x1B[3J\x1B[H"
  );
}

export default function choosePort(host: string, defaultPort: number) {
  return detect(defaultPort, host).then(
    (port) =>
      new Promise((resolve) => {
        if (port === defaultPort) {
          return resolve(port);
        }
        const message =
          process.platform !== "win32" && defaultPort < 1024 && !isRoot()
            ? `Admin permissions are required to run a server on a port below 1024.`
            : `Something is already running on port ${defaultPort}.`;
        if (isInteractive) {
          clearConsole();
          const existingProcess = getProcessForPort(defaultPort);
          const question: inquirer.QuestionCollection = {
            type: "confirm",
            name: "shouldChangePort",
            message:
              chalk.yellow(
                message +
                  `${existingProcess ? ` Probably:\n  ${existingProcess}` : ""}`
              ) + "\n\nWould you like to run the app on another port instead?",
            default: true,
          };
          inquirer.prompt(question).then((answer) => {
            if (answer.shouldChangePort) {
              resolve(port);
            } else {
              resolve(null);
            }
          });
        } else {
          console.log(chalk.red(message));
          resolve(null);
        }
      }),
    (err) => {
      throw new Error(
        chalk.red(`Could not find an open port at ${chalk.bold(host)}.`) +
          "\n" +
          ("Network error message: " + err.message || err) +
          "\n"
      );
    }
  );
}