@pierre/diffs is an open source diff and code rendering library. Built on Shiki for syntax highlighting and theming, super customizable, and packed with features. Made by The Pierre Computer Company.
Currently v1.3.0-beta.3
Enable edit mode in any File or FileDiff component with the EditorProvider. Includes support for selection management, auto-indention, undo history, find-in-file, lint markers, and more. Pairs nicely with @pierre/trees for AUI style experiences.
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import { DEFAULT_THEMES } from '@pierre/diffs';import { Editor } from '@pierre/diffs/editor';import { EditorProvider, FileDiff } from '@pierre/diffs/react';import { IconArrow, IconChevronSm, IconSparkle } from '@pierre/icons';import { FileTree, type FileTreeRowDecoration } from '@pierre/trees';import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
import './agent-ui.css';import { AUI_SESSIONS, type AuiChangedFile, type AuiSession, getFileDiff, getSessionDirectoryPaths, getSessionGitStatus, getSessionPaths,} from './mockData';
export type ThemeType = 'light' | 'dark';
// The editor's stylesheet flattens every line number to one neutral colour// (`--diffs-editor-line-number-fg`) and is injected as an unlayered <style>,// so it overrides the library's per-line colouring (which lives in @layer// base). We adopt this extra, higher-specificity unlayered sheet into the// editor's shadow root to restore jade/red numbers for added and deleted// lines, while leaving the active/selected line to the editor's own styling.const LINE_NUMBER_COLOR_CSS = `[data-column-number][data-line-type='change-addition']:not([data-selected-line]):not([data-active]) { color: var(--diffs-addition-base);}[data-column-number][data-line-type='change-deletion']:not([data-selected-line]):not([data-active]) { color: var(--diffs-deletion-base);}`;
let lineNumberColorSheet: CSSStyleSheet | null = null;function getLineNumberColorSheet(): CSSStyleSheet | null { if (typeof CSSStyleSheet === 'undefined') { return null; } if (lineNumberColorSheet == null) { lineNumberColorSheet = new CSSStyleSheet(); lineNumberColorSheet.replaceSync(LINE_NUMBER_COLOR_CSS); } return lineNumberColorSheet;}
// Renders the active session's changed files as a @pierre/trees FileTree, with// git-status colours and per-row +/- decorations. The tree is an imperative web// component, so it's created in an effect and torn down on session change.function ChangesTree({ session, activePath, themeType, onSelect,}: { session: AuiSession; activePath: string | null; themeType: ThemeType; onSelect: (path: string) => void;}) { const containerRef = useRef<HTMLDivElement | null>(null); const treeRef = useRef<FileTree | null>(null); const onSelectRef = useRef(onSelect); onSelectRef.current = onSelect;
useEffect(() => { const container = containerRef.current; if (container == null) { return; }
const filesByPath = new Map<string, AuiChangedFile>( session.changedFiles.map((file) => [file.path, file]) ); const tree = new FileTree({ paths: getSessionPaths(session), gitStatus: getSessionGitStatus(session), initialExpandedPaths: getSessionDirectoryPaths(session), density: 'compact', renderRowDecoration: ({ item }): FileTreeRowDecoration | null => { const file = filesByPath.get(item.path); if (file == null) { return null; } // `light-dark()` resolves against the tree host's color-scheme, which we // pin to the demo's own toggle, so jade/red adapt across light and dark. // Skip a zero count entirely so rows only show the side that changed. const parts: { text: string; color: string }[] = []; if (file.additions > 0) { parts.push({ text: `+${String(file.additions)}`, color: 'light-dark(#0f9d6b, #34d399)', }); } if (file.deletions > 0) { const prefix = parts.length > 0 ? '\u00a0' : ''; parts.push({ text: `${prefix}\u2212${String(file.deletions)}`, color: 'light-dark(#dc2626, #f87171)', }); } if (parts.length === 0) { return null; } return { text: parts.map((part) => part.text).join(''), title: `${String(file.additions)} additions, ${String(file.deletions)} deletions`, parts, }; }, onSelectionChange: (selectedPaths) => { for (let index = selectedPaths.length - 1; index >= 0; index -= 1) { const path = selectedPaths[index]; if (!path.endsWith('/')) { onSelectRef.current(path); break; } } }, }); treeRef.current = tree; container.innerHTML = ''; tree.render({ fileTreeContainer: container });
return () => { tree.cleanUp(); treeRef.current = null; }; }, [session]);
// Inline color-scheme beats the tree's `:host { color-scheme: light dark }`, // flipping its light-dark() colours with our toggle. useEffect(() => { if (containerRef.current != null) { containerRef.current.style.colorScheme = themeType; } }, [themeType, session]);
// Keep the highlighted row matched to the active file. useEffect(() => { const tree = treeRef.current; if (tree == null || activePath == null) { return; } const item = tree.getItem(activePath); if (item == null) { return; } for (const selectedPath of tree.getSelectedPaths()) { if (selectedPath !== activePath) { tree.getItem(selectedPath)?.deselect(); } } if (!item.isSelected()) { item.select(); } }, [activePath, session]);
return <div ref={containerRef} className="aui-tree" />;}
export interface AgentUiProps { // Theme is controlled by the parent so the toggle can live outside the // component (the homepage section renders its own button group). themeType: ThemeType; // Highlight themes the surrounding worker pool was initialized with. Defaults // to the shared homepage pool's themes. theme?: { dark: string; light: string }; // Server-rendered diff HTML keyed by file path. When present the matching // FileDiff hydrates from this markup (already syntax-highlighted) instead of // waiting on the client worker, which also avoids an SSR/client mismatch. prerenderedDiffs?: Record<string, string>;}
export function AgentUi({ themeType, theme = DEFAULT_THEMES, prerenderedDiffs,}: AgentUiProps) { const session = AUI_SESSIONS[0];
const [activePath, setActivePath] = useState<string | null>( () => session.changedFiles[0]?.path ?? null );
// Persisted in-editor edits keyed by path, so switching files keeps the // agent's tweaked output. const editsRef = useRef<Map<string, string>>(new Map()); // The editor's debounced onChange fires without a path argument, so we track // the live target here. const activeTargetRef = useRef<string | null>(null); useEffect(() => { activeTargetRef.current = activePath; }, [activePath]);
const editor = useMemo( () => new Editor({ enabledQuickEdit: true, renderQuickEdit({ close, getSelectionText, replaceSelectionText }) { const container = document.createElement('div'); const button = document.createElement('button'); container.className = 'aui-quick-edit'; button.type = 'button'; button.textContent = 'Wrap selection in TODO()'; button.addEventListener('click', () => { replaceSelectionText(`TODO(${getSelectionText()})`); close(); }); container.append(button); return container; }, onChange(file) { const target = activeTargetRef.current; if (target == null) { return; } editsRef.current.set(target, file.contents); }, }), [] );
// The changes tree shows one file at a time; selecting a file swaps the // active surface. const openFile = useCallback((path: string) => { setActivePath(path); }, []);
const activeFile: AuiChangedFile | null = useMemo( () => activePath != null ? (session.changedFiles.find((file) => file.path === activePath) ?? null) : null, [session, activePath] );
const editKey = activeFile?.path ?? '';
// Rebuild the diff surface whenever the active file changes, substituting any // persisted edits for the snapshot's `after`. const fileDiff = useMemo( () => activeFile != null ? getFileDiff(activeFile, editsRef.current.get(editKey)) : null, [activeFile, editKey] );
// Server-rendered, already-highlighted HTML for the active diff. The snapshot // is generated in dark mode, so only reuse it while the demo is in dark mode // (otherwise a freshly opened file would flash dark before re-highlighting). // It's also only safe when the file is unedited so the markup matches // `fileDiff`. const activePrerenderedHTML = themeType === 'dark' && activePath != null && editsRef.current.get(editKey) == null ? prerenderedDiffs?.[activePath] : undefined;
const breadcrumbSegments = activePath != null ? activePath.split('/') : [];
// Re-adopt the jade/red line-number override whenever the diff surface is // rebuilt (each file switch remounts the diffs-container with a fresh shadow // root). const surfaceWrapRef = useRef<HTMLDivElement | null>(null); useEffect(() => { const sheet = getLineNumberColorSheet(); if (sheet == null) { return; } const container = surfaceWrapRef.current?.querySelector('.aui-surface'); const shadowRoot = container?.shadowRoot; if (shadowRoot == null) { return; } if (!shadowRoot.adoptedStyleSheets.includes(sheet)) { shadowRoot.adoptedStyleSheets = [...shadowRoot.adoptedStyleSheets, sheet]; } }, [activePath]);
return ( <EditorProvider editor={editor}> <div className="aui" data-theme-type={themeType} data-embedded="true"> <div className="aui-body"> <section className="aui-center"> <header className="aui-center-header"> <nav className="aui-breadcrumb" aria-label="File path"> {breadcrumbSegments.length > 0 ? ( breadcrumbSegments.map((segment, index) => ( <span // Path segments are positional; index keys are stable here. key={`${segment}-${String(index)}`} className="aui-crumb" data-leaf={ index === breadcrumbSegments.length - 1 ? 'true' : undefined } > {segment} </span> )) ) : ( <span className="aui-crumb">No file selected</span> )} </nav> </header>
<div className="aui-surface-wrap" ref={surfaceWrapRef}> {activeFile != null && fileDiff != null ? ( <FileDiff key={activePath} fileDiff={fileDiff} className="aui-surface" options={{ theme, themeType, disableFileHeader: true, overflow: 'wrap', diffStyle: 'unified', }} prerenderedHTML={activePrerenderedHTML} contentEditable /> ) : ( <div className="aui-empty"> Select a changed file to review. </div> )} </div>
<div className="aui-composer"> <textarea className="aui-composer-input" placeholder="Ask for changes, @mention files, or run commands…" rows={2} disabled /> <div className="aui-composer-toolbar"> <button type="button" className="aui-composer-select" disabled> <IconSparkle className="opacity-50" /> Agent <IconChevronSm className="opacity-50" /> </button> <button type="button" className="aui-composer-select" disabled> Mythos 5 <IconChevronSm className="opacity-50" /> </button> <button type="button" className="aui-composer-send ml-auto" aria-label="Send" disabled > <IconArrow className="rotate-[90deg]" /> </button> </div> </div> </section>
<aside className="aui-changes"> <div className="aui-changes-tabs" role="tablist"> <button type="button" role="tab" disabled> All files </button> <button type="button" role="tab" aria-selected="true"> Changes </button> <button type="button" role="tab" disabled> Checks </button> </div> <ChangesTree session={session} activePath={activePath} themeType={themeType} onSelect={openFile} /> </aside> </div> </div> </EditorProvider> );}Choose from stacked (unified) or split (side-by-side). Both use CSS Grid and Shadow DOM under the hood, meaning fewer DOM nodes and faster rendering.
Editor mode (experimental) makes any code surface—File or FileDiff—editable in place. Start typing in the code below and it updates as you edit. Select text to try the custom Quick Edit action.
1234567891011121314151617181920212223242526272829303132export interface DebounceOptions { waitMs: number; trailing?: boolean;}
export function debounce<Args extends unknown[]>( fn: (...args: Args) => void, options: DebounceOptions,) { let timer: ReturnType<typeof setTimeout> | undefined;
const debounced = (...args: Args) => { if (timer != null) { clearTimeout(timer); }
timer = setTimeout(() => { timer = undefined; if (options.trailing !== false) { fn(...args); } }, options.waitMs); };
debounced.cancel = () => { clearTimeout(timer); timer = undefined; };
return debounced;}
We built @pierre/diffs on top of Shiki for syntax highlighting and general theming. Our components automatically adapt to blend in with your theme selection, including across color modes.
Love the Pierre themes? Install our Pierre Theme pack with light and dark flavors, or learn how to build your own Shiki themes.
Your diffs, your choice. Render changed lines with classic diff indicators (+/–), full-width background colors, or vertical bars. You can even highlight inline changes—character or word based—and toggle line wrapping, hide numbers, and more.
@pierre/diffs adapts to any font, font-size, line-height, and even font-feature-settings you may have set. Configure font options with your preferred CSS method globally or on a per-component basis.
38 unmodified lines394041424344454344474546474810 unmodified lines38 unmodified lines if !exists { return nil, false }
now := time.Now() expired := now.After(item.ExpiresAt) if expired { if time.Now().After(item.ExpiresAt) { delete(c.items, key) c.onEviction(key, item.Value) return nil, false }
return item.Value, true10 unmodified linesSwap between the built-in hunk separator styles and a CSS-only custom variant to preview how collapsed chunks are displayed.
Switch between lightweight header metadata and a fully custom header rendered inside the built-in data-diffs-header shell.
Render conflicts through a dedicated diff primitive that treats current and incoming sections as structured additions/deletions without running text diffing. Resolve by choosing current, incoming, or both changes and preview the updated file instantly.
19 unmodified lines20212223232425262714 unmodified lines42434444454647454647484950515253545521 unmodified lines19 unmodified linesexport async function createSession(userId: string) { await cleanupExpiredSessions(userId);
||@pierre/diffs provide a flexible annotation framework for injecting additional content and context. Use it to render your own line comments, annotations from CI jobs, and other third-party content.
2 unmodified lines345677891011121314141516171819192021222 unmodified linesfrom typing import Optional
SECRET_KEY = "your-secret-key"
def create_token(user_id: str, expires_in: int = 3600) -> str:def create_token(user_id: str, role: str = "user", expires_in: int = 3600) -> str: payload = { "sub": user_id, "role": role, "exp": time.time() + expires_in } return jwt.encode(payload, SECRET_KEY, algorithm="HS256")
def verify_token(token: str) -> Optional[str]:def verify_token(token: str) -> Optional[dict]: try: payload = jwt.decode(token, SECRET_KEY, algorithms=["HS256"]) if payload["exp"] < time.time(): return None return payload["sub"] return {"user_id": payload["sub"], "role": payload["role"]}Should we validate the role parameter? We could restrict it to a set of allowed values.
Good idea, maybe use a Literal type or an enum.
Agreed, we should also update verify_token to return the role.
Annotations can also be used to build interactive code review interfaces similar to AI-assisted coding tools like Cursor. Use it to track the state of each change, inject custom UI like accept/reject buttons, and provide immediate visual feedback.
4 unmodified lines567891091011121314152 unmodified lines4 unmodified lines <title>Welcome</title></head><body> <header> <h1>Welcome</h1> <p>Thanks for visiting</p> <h1>Welcome to Our Site</h1> <p>We're glad you're here</p> <a href="/about" class="btn">Learn More</a>Turn on line selection with enableLineSelection: true. When enabled, clicking a line number will select that line. Click and drag to select multiple lines, or hold Shift and click to extend your selection. You can also control the selection programmatically. Also selections will elegantly manage the differences between split and unified views.
Attach hover callbacks to individual syntax tokens with onTokenEnter and onTokenLeave. Here we’ve added a static CSS knowledge index to show information-rich tooltips on hover. Try hovering over CSS properties, values, and at-rules below. See the Token Hooks docs for the full API.
In addition to rendering standard Git diffs and patches, you can pass any two files in @pierre/diffs and get a diff between them. This is especially useful when comparing across generative snapshots where linear history isn't always available. Edit the css below to see the diff.
1233.pizza { display: flex; justify-content: center;}Collectively, our team brings over 150 years of expertise designing, building, and scaling the world's largest distributed systems at Cloudflare, Coinbase, Discord, GitHub, Reddit, Stripe, X, and others.