| 1 | --- |
| 2 | title: CSS content-visibility for Long Lists |
| 3 | impact: HIGH |
| 4 | impactDescription: faster initial render |
| 5 | tags: rendering, css, content-visibility, long-lists |
| 6 | --- |
| 7 | |
| 8 | ## CSS content-visibility for Long Lists |
| 9 | |
| 10 | Apply `content-visibility: auto` to defer off-screen rendering. |
| 11 | |
| 12 | **CSS:** |
| 13 | |
| 14 | ```css |
| 15 | .message-item { |
| 16 | content-visibility: auto; |
| 17 | contain-intrinsic-size: 0 80px; |
| 18 | } |
| 19 | ``` |
| 20 | |
| 21 | **Example:** |
| 22 | |
| 23 | ```tsx |
| 24 | function MessageList({ messages |
| 25 | return ( |
| 26 | <div className=" |
| 27 | {messages.map(( |
| 28 | <div key={ |
| 29 | <Avatar user= |
| 30 | <div>{msg. |
| 31 | </div> |
| 32 | ))} |
| 33 | </div> |
| 34 | ); |
| 35 | } |
| 36 | ``` |
| 37 | |
| 38 | For 1000 messages, browser skips layout/paint for ~990 off-screen items (10× faster initial render). |