Academy
hardDev Processes#89

CI/CD with GitHub Actions for RN

Prompt

Write a GitHub Actions workflow that runs on PRs to main:

  1. Installs dependencies (pnpm)
  2. Runs linter
  3. Runs tests
  4. Runs EAS build (dry-run)

Solution

name: RN CI
on:
  pull_request:
    branches: [main]
jobs:
  ci:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: pnpm/action-setup@v4
      - uses: actions/setup-node@v4
        with: { node-version: 22, cache: 'pnpm' }
      - run: pnpm install
      - run: pnpm lint
      - run: pnpm test
      - run: npx eas build --platform ios --profile preview --non-interactive
Mentor's take

This workflow is where your SDLC choice becomes enforceable. In a waterfall-shaped process, testing is a phase — defects surface weeks after they were written, at maximum fix cost. Running lint, tests, and a build on every PR turns quality into a merge gate: "no merge without green CI and one approving review" is a written exit criterion, not a habit, and the feedback loop shrinks from weeks to minutes.

Mechanics worth naming: pull_request targeting main (not push after merge — you want the gate before integration), pnpm caching via setup-node so the gate stays fast enough that nobody routes around it, and --non-interactive because EAS in CI authenticates via an EXPO_TOKEN secret, never a login prompt. The build uses a preview profile: it proves the app still compiles and bundles without burning a production build or store credentials on every PR.

The trade-off: full native builds per PR are slow and cost build-queue minutes. Defensible middle ground — lint and unit tests on every PR, native builds on merge to main or on a label. What's non-negotiable is that the check runs before merge.

Red flag: a pipeline that only runs after merge to main. That's not a gate, it's an alarm that rings after the intruder is inside.

Say it: "CI on pull requests is my merge gate — lint, tests, and a non-interactive preview build must pass before integration, so defects are caught in minutes, not found in a release branch."