# Lovable — Anthropic Sonnet 3.7 Broke our Diff Viewer

- Company: Lovable (lovable.dev)
- Announced: 2025-03-12T07:23:00+00:00
- Category: not stated
- Coverage: not counted
- Announcement: no
- Group: routine
- Source: https://lovable.dev/blog/anthropic-sonnet-3-7-lovable-diff-viewer
- Record: https://forck.live/items/12147-anthropic-sonnet-3-7-broke-our-diff-viewer
- Subject: Lovable / AI app builder

Lovable describes how upgrading to Claude 3.7 Sonnet caused its Diff Viewer to freeze when displaying 15+ modified files, because each CodeMirror instance takes 20-50ms to initialize and blocks the browser. The team implemented time slicing in React, rendering files in batches of two with 50ms delays, which turns one long blocking task into several shorter ones and keeps the interface responsive.

## Evidence

Verbatim from https://lovable.dev/blog/anthropic-sonnet-3-7-lovable-diff-viewer:

> Our solution: break the work into smaller chunks (time slicing) to keep the browser responsive.

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