Page 5 - JavaScript

JavaScript

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Floating Point Precision in JavaScript: 0.1 + 0.2 ≠ 0.3

Maxim Mironjuk - October 16, 2025

The console prints 0.30000000000000004, a price comparison fails, a sum of invoice line items is off by one cent. Floating point precision is not a JavaScript quirk, it is a consequence of IEEE 754, but it hits JavaScript developers especially often because the language only has a single number type. This article explains the cause and shows robust fixes.

JavaScript Web Performance

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Find and Fix JavaScript Memory Leaks with Chrome DevTools

Maxim Mironjuk - October 14, 2025

Memory leaks in JavaScript applications are invisible, until the browser crashes or the page noticeably slows down after a few minutes. Heap snapshots, allocation timelines and the retainer graph in Chrome DevTools make invisible memory leaks visible, locatable and fixable.

JavaScript

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JavaScript Clipboard API: Copy & Paste Without execCommand

Maxim Mironjuk - October 13, 2025

execCommand('copy') was a hack that is now marked deprecated in modern browsers. The Clipboard API delivers a clean, Promise-based interface for reading and writing the clipboard, including image and rich text support plus a built-in permission model.

JavaScript Web Performance

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Code Splitting Strategies Beyond the Basics

Maxim Mironjuk - October 04, 2025

Route splitting is the standard entry point, but the noticeable improvement often sits one level deeper. Component level splits, deliberate vendor chunking and preload hints together decide whether code splitting merely looks good in the bundle report or actually shortens load time for users.

JavaScript Security/OWASP

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Cookie Store API in Detail: Asynchronous Cookie Management Beyond document.cookie

Maxim Mironjuk - September 24, 2025

The Cookie Store API replaces the error prone parsing of document.cookie with an asynchronous, promise based interface featuring structured cookie objects, change events and real service worker access. Anyone managing session cookies, consent banners or auth tokens will find a much more robust foundation in the Cookie Store API than manual string parsing.

JavaScript Design Patterns

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Deep Equality Without an External Library: Writing Your Own Comparison Function

Maxim Mironjuk - September 16, 2025

=== only compares objects by reference identity, and JSON.stringify fails on key order, maps, sets and dates. A hand written deep equality function compares values recursively by structure instead of reference and covers exactly the data types the simple approaches regularly fail on.

JavaScript Alpine.js TypeScript

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JavaScript Custom Events: Component Communication Without a Framework

Maxim Mironjuk - September 16, 2025

Prop drilling and global variables are signs of tight coupling. Custom Events offer a native DOM solution: components send events, others listen, without a direct reference to each other, without a framework, and with full TypeScript support.

JavaScript Web Performance

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JavaScript Performance API: Precise Runtime Measurement with performance.now() and PerformanceObserver

Maxim Mironjuk - September 11, 2025

Date.now() delivers milliseconds with a precision that is not sufficient for serious performance measurement, and falls into the trap of system clock synchronization. The JavaScript Performance API provides sub-millisecond timestamps, structured marks and measures, a non-blocking observer mechanism, and direct access to Web Vitals without an external library.

JavaScript TypeScript

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Promise.withResolvers() in JavaScript: The Deferred Pattern Without Boilerplate

Maxim Mironjuk - September 06, 2025

Anyone who wanted to resolve a promise from the outside, from an event handler, a callback API, or some other asynchronous context, had to smuggle resolve and reject out of the constructor scope. Promise.withResolvers() solves this in a single line: { promise, resolve, reject } as a structured object, clear and without boilerplate.

JavaScript Web Performance

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JavaScript IndexedDB: Using the Browser's Offline Database Correctly

Maxim Mironjuk - September 06, 2025

IndexedDB is the most powerful offline storage solution in the browser: structured data, gigabyte-scale capacity, transactions, indexes and asynchronous queries without ever blocking the UI thread. Once you master the fundamentals, you can build offline-first apps that work fully even without a network connection.