Javascript Pro

Table of Contents

• When to use
• Required inputs
• Deliverables
• Core Practices
• Async Safety
• Examples
• Failure mode
• Gotchas

When to use

• Use for JavaScript implementation and review tasks.
• Use when async behavior or runtime compatibility is critical.

Required inputs

• Target runtime and module format.
• Files or functions to update.
• Error or performance constraints.

Deliverables

• Behavior-correct JavaScript changes.
• Clear async flow and explicit error handling.
• Compatibility notes when needed.

Core Practices

• Prefer small pure functions for transformation logic.
• Use const by default, let only when reassignment is required.
• Keep API surfaces explicit and documented through JSDoc when needed.

Async Safety

• Await every promise that affects correctness.

• Use Promise.all only for truly independent operations.

• Surface actionable errors with context.

• Redact secrets, tokens, credentials, and sensitive data by default.

Examples

export async function loadJson(url) {
  const response = await fetch(url)
  if (!response.ok) throw new Error(`Fetch failed: ${response.status}`)
  return response.json()
}

Failure mode

• If side effects cannot be isolated, keep behavior unchanged and document risk.

Gotchas

• Unawaited promises can mask production failures.

See Also

Topic map: [[agent-ops]]

Philosophy

• Optimize for clear, verifiable outcomes with the minimum necessary changes.
• Keep guidance deterministic so repeated runs produce consistent decisions.

Procedure

1. Confirm scope, constraints, and required inputs before edits.
2. Apply focused changes tied directly to the requested outcome.
3. Re-run the highest-signal validations and capture concrete evidence.

Validation

• Run the relevant local checks for touched files and workflow contracts.
• Fail fast: stop at the first blocking validation failure and report exact evidence.
• Re-run checks after fixes and record residual risk if any remains.

Anti-patterns

• Skipping validation after making changes.
• Applying broad refactors to solve narrow issues.
• Assuming behavior without evidence from current checks.

References and assets

• Open deep guidance: Infrastructure/references/deep-guidance.md
• Read when: the task needs advanced edge cases, migration-safe patterns, or runtime-specific nuance beyond the core checklist.