index.js

const core = require('@actions/core');
const { exec } = require('@actions/exec');
const github = require('@actions/github');
const { Toolkit } = require('actions-toolkit');

const STRATEGIES = ['#patch', '#minor', '#major'];

Toolkit.run(async (tools) => {
  {
    try {
      // get context
      const { payload } = github.context;
      const args = { message: '', email: '', username: '' };

      if (payload.head_commit) {
        args.email = payload.head_commit.committer.email;
        args.username = payload.head_commit.committer.username;
        args.message = payload.head_commit.message;
      }

      // get input credentials
      const inputUser = core.getInput('user');
      const inputEmail = core.getInput('email');
      const inputBranch = core.getInput('branch');
      const unrelated = core.getInput('unrelated');

      const { message, email, username } = args;

      const userName = inputUser || username;
      const userEmail = inputEmail || email;

      if (!userName || !userEmail) {
        const errorMessage = `failed to extract username or email from github context, please provide 'username' and 'email' through the workflow file.`;
        return core.setFailed(errorMessage);
      }

      const defaultStrategy = STRATEGIES.filter((strat) => message && message.includes(strat))[0] || STRATEGIES[0];
      const strategy = defaultStrategy.replace('#', '');
      const commitMessage = message && message.replace(defaultStrategy, '');

      tools.log(`Latest commit message: ${commitMessage}`);
      tools.log(`Running with ${userName} ${userEmail} and bumping strategy ${strategy}`);
      tools.log(`Branch is ${inputBranch}`);

      // git login and pull
      const pullArgs = ['pull', 'origin', inputBranch, '--tags'];
      if (unrelated) {
        pullArgs.push('--allow-unrelated-histories');
      }

      await exec('git', ['config', '--local', 'user.name', userName]);
      await exec('git', ['config', '--local', 'user.email', userEmail]);
      await exec('git', pullArgs);

      // version by strategy

      await exec('npm', ['version', strategy, '--no-commit-hooks', '-m', `${commitMessage} %s`]);

      const version = tools.getPackageJSON().version;
      core.info(`version is ${version}`);

      // push new version and tag
      await exec('git', ['push', 'origin', `HEAD:${inputBranch}`, '--tags']);

      // set output version
      core.setOutput('version', version);
    } catch (error) {
      core.setFailed(error.message);
    }
  }
});