main.ts

import * as core from "@actions/core";
import * as github from "@actions/github";
import matcher from "matcher";
import { getConfig } from "./config";
import { ConfigEntry } from "./ConfigEntry";

const CONFIG_FILENAME = "pr-branch-labeler.yml";
const defaults: ConfigEntry[] = [
  { label: "feature", head: "feature/*", base: undefined },
  { label: "bugfix", head: ["bugfix/*", "hotfix/*"], base: undefined },
  { label: "chore", head: "chore/*", base: undefined }
];

// Export the context to be able to mock the payload during tests.
export const context = github.context;

export async function run() {
  const repoToken: string = core.getInput("repo-token", { required: true });

  core.debug(`context: ${context ? JSON.stringify(context) : ''}`);

  if (context && context.payload && context.payload.repository && context.payload.pull_request) {
    const octokit = new github.GitHub(repoToken);
    const repoConfig: ConfigEntry[] = await getConfig(octokit, CONFIG_FILENAME, context);
    core.debug(`repoConfig: ${JSON.stringify(repoConfig)}`);
    const config: ConfigEntry[] = repoConfig.length > 0 ? repoConfig : defaults;
    core.debug(`config: ${JSON.stringify(config)}`);
    const headRef = context.payload.pull_request.head.ref;
    const baseRef = context.payload.pull_request.base.ref;
    const labelsToAdd = config.reduce((labels: string[], entry) => {
      if (entry.head && entry.base) {
        if (isMatch(headRef, entry.head) && isMatch(baseRef, entry.base)) {
          core.info(`Matched "${headRef}" to "${entry.head}" and "${baseRef}" to "${entry.base}". Setting label to "${entry.label}"`);
          labels.push(entry.label);
        }
      } else if (entry.head && isMatch(headRef, entry.head)) {
        core.info(`Matched "${headRef}" to "${entry.head}". Setting label to "${entry.label}"`);
        labels.push(entry.label);
      } else if (entry.base && isMatch(baseRef, entry.base)) {
        core.info(`Matched "${baseRef}" to "${entry.base}". Setting label to "${entry.label}"`);
        labels.push(entry.label);
      }

      return labels;
    }, []);

    if (labelsToAdd.length > 0) {
      core.debug(`Adding labels: ${labelsToAdd}`);
      await octokit.issues.addLabels({
        issue_number: context.payload.pull_request.number,
        labels: labelsToAdd,
        ...context.repo
      });
    }
  }
}

function isMatch(ref: string, patterns: string | string[]): boolean {
  return Array.isArray(patterns)
    ? patterns.some(pattern => matcher.isMatch(ref, pattern))
    : matcher.isMatch(ref, patterns);
}

try {
  run();
} catch (error) {
  core.error(`ERROR! ${JSON.stringify(error)}`);
  core.setFailed(error.message);
  throw error;
}