A clean implementation of custom HTML5 video controls (play/pause, volume, playback rate, skip buttons, progress scrubber) built as a standalone module. Demonstrates proper event binding on video element (click, play, pause, timeupdate), range input handling for volume/rate, and progress bar scrubbing via mouse events. The logic is isolated in a separate JS file and could be extracted into a reusable video player component with minimal changes - mainly parameterizing the selector queries.

Demonstrates a complete localStorage persistence pattern: loading initial state from JSON.parse(localStorage.getItem()), updating state on user actions, and serializing back with JSON.stringify(). The addItem/populateList/toggleDone functions form a coherent mini-state-management pattern that's directly applicable to any simple client-side list app. The event delegation on the list container for checkbox toggling (using data-index attributes) is a clean touch.

Shows proper usage of the Web Speech API's SpeechRecognition interface: handling interim vs final results, auto-restarting on 'end' event for continuous listening, and filtering transcript text (profanity replacement). The pattern of creating new <p> elements for each final result while updating a single element for interim results is a practical UX pattern for live transcription apps.

Contains a well-implemented, reusable debounce utility function (configurable wait/immediate) applied to scroll-based animation triggering. The checkSlide logic calculates element visibility using scrollY, innerHeight, and element offsets - a lightweight alternative to IntersectionObserver for simple scroll animations. The debounce function itself is extractable as a general-purpose utility.

Demonstrates dynamic CSS custom property manipulation via JavaScript: reading input values (including data-sizing attributes for units) and updating :root properties with document.documentElement.style.setProperty(). This pattern enables real-time theming, user-preference persistence, and design token systems without CSS-in-JS libraries.

Implements the classic 'shift-click to select range' pattern (like Gmail's checkbox selection). Tracks lastChecked element, uses a boolean flag (inBetween) toggled when encountering either boundary element, and checks all checkboxes in between. Clean, framework-free implementation of a common UX pattern that's directly reusable in any tabular data interface.

Shows a canvas drawing loop with hue-cycling stroke colors and dynamic line width oscillation. Demonstrates proper mousedown/mousemove/mouseup/mouseout event handling for drawing, ctx.getImageData/putImageData for pixel manipulation (though commented out), and HSL color space animation. The core drawing loop pattern is extractable for any freehand drawing or signature capture feature.

Implements click-and-drag horizontal scrolling (like a trackpad swipe) on a flex container. Tracks mousedown position, calculates drag distance on mousemove, and applies to scrollLeft with a multiplier. Handles mouseleave/mouseup cleanup. A reusable pattern for any horizontally overflowing carousel or timeline component that needs mouse-based navigation.