How to notify NPM package version update to user?

Question

I have written a CLI tool in Node JS and published to NPM. Every time it's run in terminal, I need the user to be notified of a new version available and its type (patch | minor | major) so that he/she can update it accordingly. How can I implement this?

Moreover, is it possible to ask the user if he/she would like to have the package updated by itself?

A new version of Rapid React is available. Would you like to update it now?(Y\n)

Answer 1

Version Update Check:

I would suggest using update-notifier but strangely it doesn't work. So, I chose to handle this work by myself.

The latest version can be checked easily with package-json which fetches the metadata of a package from the npm registry. Alternatively latest-version can be used as well which uses package-json under the hood.

import boxen from 'boxen';
import chalk from 'chalk';
import semver from 'semver';
import pkgJson from 'package-json';
import semverDiff from 'semver-diff';

import { capitalizeFirstLetter } from '../utils';

import { name, version } from '../../package.json';

const checkUpdate = async () => {
  const { version: latestVersion } = await pkgJson(name);

  // check if local package version is less than the remote version
  const updateAvailable = semver.lt(version, latestVersion as string);

  if (updateAvailable) {
    let updateType = '';

    // check the type of version difference which is usually patch, minor, major etc.
    let verDiff = semverDiff(version, latestVersion as string);

    if (verDiff) {
      updateType = capitalizeFirstLetter(verDiff);
    }

    const msg = {
      updateAvailable: `${updateType} update available ${chalk.dim(version)} → ${chalk.green(latestVersion)}`,
      runUpdate: `Run ${chalk.cyan(`npm i -g ${name}`)} to update`,
    };

    // notify the user about the available udpate
    console.log(boxen(`${msg.updateAvailable}\n${msg.runUpdate}`, {
      margin: 1,
      padding: 1,
      align: 'center',
    }));
  }
};

Update notification:

Every time the tool runs, user would see such a notification if an update is available.