Mediator Pattern in JavaScript: Practical JS Example
Mediator pattern in JavaScript: central coordinator, reduced coupling between components, when to prefer it over Observer, and a small runnable example.
JavaScript Observer pattern (EventTarget and custom pub/sub)
Implement the Observer pattern in JavaScript with EventTarget, callback lists, Pub/Sub differences, error handling, and avoiding listener leaks.
JavaScript Singleton Pattern with Class and Module Examples
Learn the JavaScript singleton pattern with class-based singleton, module singleton, getInstance examples, and when to avoid global state.
JavaScript Mouse Events: click, dblclick, mousedown, mouseup and mouseover
JavaScript mouse events: click, dblclick, mousedown, mouseup, mouseover, mouseenter, mouseout, mouseleave, mousemove, target, and coordinates—with Node-friendly snippets where possible.
JavaScript Remove Element from DOM with remove() and removeChild()
Learn how to remove DOM elements in JavaScript using element.remove(), parentNode.removeChild(), querySelector(), event handlers, and safe null checks.
JavaScript Replace DOM Element with replaceChild() and replaceWith()
Learn how to replace DOM elements in JavaScript using replaceChild(), replaceWith(), createElement(), text replacement, and safe element checks.
JavaScript scrollTo(): Scroll Window or Element Position
Learn JavaScript scrollTo() with window.scrollTo(), smooth scrolling, scroll to element, scrollIntoView(), and scroll position examples.
JavaScript YAML Parser: Parse YAML in Node.js
Learn how to parse YAML in JavaScript and Node.js with yaml and js-yaml, read YAML files, convert YAML to JSON, and handle parser errors safely.
JavaScript return vs throw: When to Return Errors or Throw
Understand return vs throw in JavaScript, when to return error values, when to throw errors, and how try...catch handles exceptions.
JavaScript JSON.parse(): Parse JSON Strings, Objects, and Files
JSON.parse in JavaScript: valid JSON strings, SyntaxError on bad input, reviver functions, and safe parsing habits.
Factorial Function in JavaScript Using Recursion
Learn how to write a factorial function in JavaScript using recursion, base cases, input validation, and an iterative alternative.
JavaScript Recursive Map Object: Transform Nested Values
Learn how to recursively map over a JavaScript object, transform nested values, preserve arrays, and create a new object without mutating input data.
JavaScript Recursive Search in Array of Objects
Learn how to recursively search an array of objects in JavaScript, find nested objects by ID, return all matches, and search child arrays safely.
JavaScript Recursive Generator with yield* Examples
Learn JavaScript recursive generators with function*, yield, yield*, tree traversal, converting generators to arrays, and practical examples.
JavaScript Pattern Matching with RegExp Examples
Learn JavaScript pattern matching with regular expressions using search(), match(), matchAll(), replace(), split(), and the RegExp constructor.
JavaScript Optional Parameters and Default Values
JavaScript optional parameters: default parameters, undefined vs null, options objects, destructuring defaults, and arguments.length patterns.
JavaScript Promise.reject(): Create and Handle Rejected Promises
Learn Promise.reject() in JavaScript with catch(), async/await, error handling, Promise.resolve comparison, and tested rejection examples.
JavaScript Promise.resolve(): Create Resolved Promises
Learn Promise.resolve() in JavaScript with resolved values, existing promises, thenables, async functions, and Promise.reject comparison.
JavaScript Promise.race (first settled promise)
JavaScript Promise.race explained: first settled promise wins, timeout patterns, empty iterable, non-Promise inputs, and how it differs from Promise.all and Promise.any. Every sample output was run on Node.js (V8).
JavaScript Set add(): Add Values to a Set
Learn JavaScript Set add() with examples showing unique values, chaining, object references, has(), size, and converting a Set to an array.
JavaScript NodeList: querySelectorAll, forEach, and Array.from
Learn JavaScript NodeList with practical examples. Understand NodeList vs Array, NodeListOf, querySelectorAll, forEach, Array.from, static NodeList behavior, and NodeList vs HTMLCollection.
JavaScript querySelector(): Select DOM Elements with CSS Selectors
Learn JavaScript querySelector() with CSS selectors, document.querySelector(), querySelectorAll(), null checks, selector errors, and practical DOM examples.
JavaScript parseFloat(): Convert Strings to Decimal Numbers
Learn how JavaScript parseFloat() converts strings to decimal numbers, how it handles trailing characters, NaN, scientific notation, and how it differs from Number().
JavaScript startsWith(): Check if a String Starts With Text
Learn JavaScript startsWith() with examples for checking string prefixes, using the position argument, case sensitivity, and alternatives.
JavaScript String Contains: includes(), indexOf(), and Regex
Learn how to check if a JavaScript string contains a substring using includes(), indexOf(), regular expressions, position checks, and case-insensitive search.
JavaScript Print Object: console.log and JSON.stringify Examples
Learn how to print objects in JavaScript using console.log(), JSON.stringify(), console.table(), Object.keys(), Object.values(), and object entries.
JavaScript Redirect to URL with location.href, assign, and replace
Learn JavaScript redirect methods using window.location.href, location.assign(), location.replace(), relative URLs, and redirect behavior in browser history.
JavaScript slice(): Array and String Examples
Learn JavaScript slice() for arrays and strings, including start/end indexes, negative indexes, shallow copy behavior, and slice vs splice.
JavaScript Send Tab Key and Detect Tab Key Press
Learn how to detect the Tab key in JavaScript, understand keyCode 9, handle KeyboardEvent.key, and why browsers restrict simulated Tab navigation.
JavaScript Sort by Date: Ascending and Descending Examples
Learn how to sort dates in JavaScript using Array.sort(), Date objects, timestamps, ascending and descending order, and safe ISO date strings.