Consider converting from bash to JavaScript for cleaner API interactions

[DerekRoberts]

Problem

The current bash implementation requires:

• Manual API URL construction
• curl + jq for API calls and JSON parsing
• Complex string manipulation for extracting PR numbers (e.g., sed -n 's|^queue/[^/]*/pr-\([0-9]\+\).*|\1|p')
• Multiple fallback strategies that are harder to maintain in bash
• Limited testability (requires GitHub Actions environment)
• Harder for JS/TS developers to contribute and maintain

Proposed Solution

Convert the action from a composite (bash) action to a Node.js action using:

• @actions/core for GitHub Actions integration
• @actions/github with Octokit for clean API calls
• TypeScript for type safety and better maintainability
• Native JavaScript for better error handling

Benefits

Organizational

1. Team alignment: Organization is stronger with JS/TS than bash
2. Easier contributions: More developers can review and contribute
3. Better code reviews: TypeScript makes intent clearer
4. Consistency: Aligns with other actions/tooling in the organization

Technical

1. Cleaner API calls: Use Octokit SDK instead of curl + jq

   // Instead of: curl + jq parsing
   const { data: pulls } = await octokit.rest.repos.listPullRequestsAssociatedWithCommit({
     owner, repo, commit_sha: sha
   });
   pr = pulls.length > 0 ? pulls[0].number.toString() : null;

2. Better error handling: Native try/catch and error objects
3. More maintainable: Easier to read and modify logic
4. No external dependencies: No need for jq in the runner
5. Type safety: TypeScript catches errors at compile time
6. Testability: Unit tests with mocked GitHub API
7. Simpler string manipulation: Native regex instead of sed/grep chains

Readability Example

Bash (current):

pr=$(echo "${MERGE_GROUP_HEAD_REF}" | sed -n 's|^queue/[^/]*/pr-\([0-9]\+\).*|\1|p')

TypeScript (proposed):

const match = headRef.match(/^queue\/[^\/]+\/pr-(\d+)/);
const pr = match ? match[1] : null;

Migration Plan

Phase 1: Setup

1. Create package.json with dependencies:
   • @actions/core
   • @actions/github
   • typescript
   • @types/node
   • @vercel/ncc (for bundling)
2. Add TypeScript config (tsconfig.json)
3. Add build scripts and GitHub Actions workflow for building

Phase 2: Implementation

1. Create src/main.ts with TypeScript implementation
2. Port all event handlers (pull_request, merge_group, push, release, workflow_dispatch)
3. Implement helper functions:
   • getPrFromApi() using Octokit
   • getPrFromGit() using simple-git or exec
   • logDebug() using @actions/core
4. Update action.yml to use node16 or node20 instead of composite

Phase 3: Testing

1. Add unit tests with Jest/Vitest
2. Mock GitHub API responses
3. Test all event types
4. Update existing workflow tests to verify compatibility

Phase 4: Rollout

1. Create feature branch
2. Test in staging/test workflows
3. Merge and release as minor version (backward compatible)
4. Monitor for issues

File Structure

action-get-pr/
├── src/
│   └── main.ts          # Main action logic
├── __tests__/
│   └── main.test.ts     # Unit tests
├── dist/
│   └── index.js         # Bundled output (git-ignored)
├── action.yml           # Updated to use node
├── package.json
├── tsconfig.json
└── .github/workflows/
    └── build.yml        # Build and test workflow

Considerations

• Action size: Will be slightly larger, but Node.js is already in runners
• Build step: Need to bundle with ncc and commit dist/index.js
• Backward compatibility: Should maintain same inputs/outputs
• Migration effort: ~108 lines of bash → ~200-300 lines of TypeScript (with tests)

Related

This would simplify the implementation added in #29 for workflow_dispatch support and improve maintainability for the team.