javascript-development

JavaScript Development

Optimized for ECMAScript 2024+, Node.js 22+, TypeScript 5.5+, and modern browser or server-first JavaScript runtimes.

Expert guidance for writing modern JavaScript code with ES2024+ features, async programming patterns, DOM manipulation, API integration, and best practices following official JavaScript resources at https://developer.mozilla.org/en-US/docs/Web/JavaScript.

• Leverage native parallel subagent dispatch and 200k+ context windows where available.

Anti-Patterns

• Copying outdated browser or framework patterns: Deprecated APIs and old workarounds add complexity immediately.
• Skipping abort, timeout, or response checks in async code: Network paths fail at the edges first, not on the happy path.
• Treating accessibility as a final polish pass: Markup and state shape are harder to fix after the component contract is set.

Verification Protocol

Before claiming "skill applied successfully":

1. Pass/fail: The Javascript Development implementation names the target runtime, framework version, and affected files.
2. Pass/fail: Build, lint, test, or equivalent local validation is run for the changed surface.
3. Pass/fail: Edge cases for errors, dependency drift, and environment differences are addressed or explicitly out of scope.
4. Pressure-test scenario: Apply the workflow to a change that passes happy-path tests but fails one boundary condition.
5. Success metric: Zero untested success claims; every implementation claim maps to a command or artifact.

Before and After Example

// Before
async function loadProfile() {
  const response = await fetch('/api/profile');
  return response.json();
}

// After
export async function loadProfile(signal) {
  const response = await fetch('/api/profile', { signal });
  if (!response.ok) {
    throw new Error(`Profile request failed: ${response.status}`);
  }
  return response.json();
}

Adds cancellation and explicit response validation so network failures do not masquerade as parsing bugs.