Front End Development Performance & Optimization Flashcards
6 cards from real Front End Development practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Front End Development Performance & Optimization flashcards as text
Which browser developer tool metric measures the time until the largest visible content element is rendered?
Answer: Largest Contentful Paint
Largest Contentful Paint (LCP) measures when the largest image or text block is rendered within the viewport, a key Core Web Vital.
What is tree shaking in the context of JavaScript bundlers?
Answer: Removing unused code from the final bundle
Tree shaking statically analyzes import/export statements and eliminates dead (unused) code from the final JavaScript bundle.
Which CSS technique avoids layout reflow by using transform for animations instead of top/left?
Answer: GPU compositing via transform
Using CSS transform promotes elements to their own compositor layer, avoiding costly layout reflow and paint operations.
What does the HTML attribute 'loading="lazy"' on an tag enable?
Answer: Defers loading the image until it's near the viewport
The loading='lazy' attribute tells the browser to defer loading an image until it's close to entering the viewport.
What is code splitting in front-end development?
Answer: Dividing a JavaScript bundle into smaller chunks loaded on demand
Code splitting breaks a large JavaScript bundle into smaller chunks that are loaded only when needed, reducing initial page load time.
Which performance metric measures unexpected layout shifts experienced by users?
Answer: Cumulative Layout Shift
Cumulative Layout Shift (CLS) measures the total amount of unexpected layout shifts that occur during a page's lifetime.
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