Javascript Modern

javascript-modern

Acknowledgement: Shared by Peter Bamuhigire, techguypeter.com, +256 784 464178.

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...

Workflow

• 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.

Evidence Produced

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.

phpCopy code
<!-- 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>

javascriptCopy code
// 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)

javascriptCopy code
// 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.

Decision Rules

Capability Contract

Read and search are required. Editing and browser or test execution require authorisation; network access is optional.

Degraded Mode

Fallback: without execution, provide a patch plus exact lint, unit, and browser checks still required.

Domain Anti-Patterns

• Starting asynchronous work without handling rejection.
• Using global mutable state instead of module scope.
• Adding a dependency for a native language operation.
• Blocking the main thread with large synchronous transforms.
• Changing module format without checking runtime compatibility.

Inputs

Outputs

• Produce reviewed JavaScript, findings, tests, and compatibility notes.