javascript-modern

name	javascript-modern
description	Modern JavaScript (ES6+) patterns for PHP+JavaScript SaaS apps: modules, async/await, destructuring, Proxy/Reflect, generators, WeakMap/WeakSet, optional chaining, error handling, and performance patterns. Use when writing JavaScript for web...
metadata	{"portable":true,"compatible_with":["Codex","codex"]}

javascript-modern

Acknowledgement: Shared by Peter Bamuhigire, techguypeter.com, [phone].

Use When

• Modern JavaScript (ES6+) patterns for PHP+JavaScript SaaS apps: modules, async/await, destructuring, Proxy/Reflect, generators, WeakMap/WeakSet, optional chaining, error handling, and performance patterns. Use when writing JavaScript for web...
• The task needs reusable judgment, domain constraints, or a proven workflow rather than ad hoc advice.

Do Not Use When

• The task is unrelated to javascript-modern or would be better handled by a more specific companion skill.
• The request only needs a trivial answer and none of this skill's constraints or references materially help.

Required Inputs

• Gather relevant project context, constraints, and the concrete problem to solve; load references only as needed.
• Confirm the desired deliverable: design, code, review, migration plan, audit, or documentation.

Workflow

• Read this SKILL.md first, then load only the referenced deep-dive files that are necessary for the task.
• For OOP-heavy browser modules, reusable UI widgets, or complex stateful workflows, pair with references/javascript-patterns.md and load references/javascript-patterns.md.
• For Node/runtime container work, pair with docker-development.
• Apply the ordered guidance, checklists, and decision rules in this skill instead of cherry-picking isolated snippets.
• Produce the deliverable with assumptions, risks, and follow-up work made explicit when they matter.

Quality Standards

• Keep outputs execution-oriented, concise, and aligned with the repository's baseline engineering standards.
• Preserve compatibility with existing project conventions unless the skill explicitly requires a stronger standard.
• Prefer deterministic, reviewable steps over vague advice or tool-specific magic.

Anti-Patterns

• Treating examples as copy-paste truth without checking fit, constraints, or failure modes.
• Loading every reference file by default instead of using progressive disclosure.

Outputs

• A concrete result that fits the task: implementation guidance, review findings, architecture decisions, templates, or generated artifacts.
• Clear assumptions, tradeoffs, or unresolved gaps when the task cannot be completed from available context alone.
• References used, companion skills, or follow-up actions when they materially improve execution.

Evidence Produced

Category	Artifact	Format	Example
Correctness	JavaScript module test plan	Markdown doc covering async, generators, Proxy, and module boundary tests	docs/web/js-module-tests.md

References

• Use the references/ directory for deep detail after reading the core workflow below.
• Use references/javascript-advanced.md when the task needs deeper ES language mechanics, async patterns, metaprogramming, or performance.
• Use references/javascript-patterns.md when the task involves OOP, prototypes, design patterns, event modules, or maintainable browser architecture.

Expert-level ES6+ patterns for PHP+JavaScript SaaS developers. Assumes fluency with variables, loops, and functions.

Architecture Rule (Non-Negotiable)

JavaScript belongs in its own .js files. PHP only emits a <script src="..."> tag or passes config via a single JSON data attribute. No <?php echo $var ?> scattered through JS files.

<!-- PHP emits one data attribute — no inline JS -->
<div id="app-config"
     data-config='<?= json_encode($config, JSON_HEX_APOS) ?>'
     data-user='<?= json_encode(['id' => $user->id, 'role' => $user->role]) ?>'>
</div>

// assets/js/app.js — reads config cleanly from its own file
const config = JSON.parse(document.getElementById('app-config').dataset.config);
const user   = JSON.parse(document.getElementById('app-config').dataset.user);

---

1. Module Pattern (IIFE + ES Modules)

// assets/js/modules/user-table.js
const UserTable = (() => {
    let tableInstance = null;           // private — unreachable from outside

    function init(config) { tableInstance = new DataTable('#users-table', config); }
    function refresh()    { tableInstance?.ajax.reload(); }

    return { init, refresh };           // public API only
})();

export default UserTable;

// Named exports for shared utilities: assets/js/core/utils.js
export function debounce(fn, delay) { /* ... */ }
export function throttle(fn, limit) { /* ... */ }

---

Additional Guidance

Extended guidance for javascript-modern was moved to references/skill-deep-dive.md to keep this entrypoint compact and fast to load.

Use that deep dive for:

• 2. Async/Await — The Right Patterns
• 3. Production-Grade Fetch Wrapper
• 4. Destructuring — Beyond the Basics
• 5. Optional Chaining and Nullish Coalescing
• 6. Generators for Pagination / Lazy Data
• 7. WeakMap for Private Data and DOM Metadata
• 8. Proxy for Validation and Reactivity
• 9. Error Handling Strategy
• 10. Event Delegation (Performance Pattern)
• 11. Debounce and Throttle
• 12. LocalStorage with Expiry
• 13. const/letand Arrow Functionthis``
• Additional deep-dive sections continue in the reference file.