feat(split-pane): refactor to generic n-pane SplitPane with cookie persistence

New API: panes[], defaultSplit[], cookieKey, tabLabels. Supports arbitrary
number of panes with n-1 draggable dividers and JSON cookie persistence.
Replaces TriplePane; mobile renders tabs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Janpeter Visser 2026-04-30 17:07:02 +02:00
parent 6cd98129f2
commit 0e34f67be5
2 changed files with 107 additions and 215 deletions

View file

@ -1,70 +1,106 @@
'use client'
import { useRef, useState, useEffect, useCallback } from 'react'
import { Fragment, useRef, useState, useEffect, useCallback } from 'react'
import { cn } from '@/lib/utils'
const COOKIE_PREFIX = 'split-pane:'
const COOKIE_PREFIX = 'sp:'
const COOKIE_MAX_AGE = 60 * 60 * 24 * 365
function readSplitCookie(key: string): number | null {
function readSplits(cookieKey: string, n: number): number[] | null {
if (typeof document === 'undefined') return null
const match = document.cookie.match(new RegExp(`(?:^|; )${COOKIE_PREFIX}${key}=([^;]+)`))
const match = document.cookie.match(
new RegExp(`(?:^|; )${COOKIE_PREFIX}${cookieKey}=([^;]+)`)
)
if (!match) return null
const val = parseFloat(decodeURIComponent(match[1]))
return !isNaN(val) && val > 0 && val < 100 ? val : null
try {
const parsed: unknown = JSON.parse(decodeURIComponent(match[1]))
if (
!Array.isArray(parsed) ||
parsed.length !== n ||
parsed.some((v) => typeof v !== 'number') ||
Math.abs((parsed as number[]).reduce((a, b) => a + b, 0) - 100) > 1
) return null
return parsed as number[]
} catch {
return null
}
}
function writeSplitCookie(key: string, value: number) {
document.cookie = `${COOKIE_PREFIX}${key}=${value}; max-age=${COOKIE_MAX_AGE}; path=/; samesite=lax`
function writeSplits(cookieKey: string, splits: number[]) {
document.cookie = `${COOKIE_PREFIX}${cookieKey}=${encodeURIComponent(
JSON.stringify(splits)
)}; max-age=${COOKIE_MAX_AGE}; path=/; samesite=lax`
}
interface SplitPaneProps {
left: React.ReactNode
right: React.ReactNode
storageKey: string
defaultSplit?: number // percentage for left pane
minSize?: number // minimum px per pane, default 200
export interface SplitPaneProps {
panes: React.ReactNode[]
defaultSplit: number[] // length n, values sum to 100
cookieKey: string
tabLabels?: string[] // mobile tab labels, defaults to "Pane N"
minSize?: number // minimum px per pane, default 200
mobileBreakpoint?: number // default 1024
}
export function SplitPane({
left,
right,
storageKey,
defaultSplit = 20,
panes,
defaultSplit,
cookieKey,
tabLabels,
minSize = 200,
mobileBreakpoint = 1024,
}: SplitPaneProps) {
const n = panes.length
const containerRef = useRef<HTMLDivElement>(null)
const [split, setSplit] = useState<number>(() => {
return readSplitCookie(storageKey) ?? defaultSplit
})
const [isDragging, setIsDragging] = useState(false)
const [isMobile, setIsMobile] = useState(false)
const [activeTab, setActiveTab] = useState<'left' | 'right'>('left')
const splitsRef = useRef<number[]>(defaultSplit)
const [splits, setSplits] = useState<number[]>(() => {
return readSplits(cookieKey, n) ?? defaultSplit
})
const [dragging, setDragging] = useState<number | null>(null) // divider index (0..n-2)
const [isMobile, setIsMobile] = useState(false)
const [activeTab, setActiveTab] = useState(0)
useEffect(() => { splitsRef.current = splits }, [splits])
// Detect mobile
useEffect(() => {
const check = () => setIsMobile(window.innerWidth < 1024)
const check = () => setIsMobile(window.innerWidth < mobileBreakpoint)
check()
window.addEventListener('resize', check)
return () => window.removeEventListener('resize', check)
}, [])
}, [mobileBreakpoint])
const onMouseMove = useCallback((e: MouseEvent) => {
if (!isDragging || !containerRef.current) return
if (dragging === null || !containerRef.current) return
const rect = containerRef.current.getBoundingClientRect()
const containerWidth = rect.width
const offsetX = e.clientX - rect.left
const minPct = (minSize / containerWidth) * 100
const maxPct = 100 - minPct
const newSplit = Math.min(maxPct, Math.max(minPct, (offsetX / containerWidth) * 100))
setSplit(newSplit)
writeSplitCookie(storageKey, newSplit)
}, [isDragging, minSize, storageKey])
const onMouseUp = useCallback(() => setIsDragging(false), [])
const cursorPct = ((e.clientX - rect.left) / containerWidth) * 100
const current = splitsRef.current
// Left edge of pane[dragging] in percentage
const leftEdge = current.slice(0, dragging).reduce((a, b) => a + b, 0)
const combinedWidth = current[dragging] + current[dragging + 1]
const newLeft = Math.min(Math.max(cursorPct - leftEdge, minPct), combinedWidth - minPct)
const newRight = combinedWidth - newLeft
setSplits((prev) => {
const next = [...prev]
next[dragging] = newLeft
next[dragging + 1] = newRight
return next
})
}, [dragging, minSize])
const onMouseUp = useCallback(() => {
if (dragging !== null) {
writeSplits(cookieKey, splitsRef.current)
setDragging(null)
}
}, [dragging, cookieKey])
useEffect(() => {
if (isDragging) {
if (dragging !== null) {
window.addEventListener('mousemove', onMouseMove)
window.addEventListener('mouseup', onMouseUp)
}
@ -72,37 +108,29 @@ export function SplitPane({
window.removeEventListener('mousemove', onMouseMove)
window.removeEventListener('mouseup', onMouseUp)
}
}, [isDragging, onMouseMove, onMouseUp])
}, [dragging, onMouseMove, onMouseUp])
if (isMobile) {
return (
<div className="flex flex-col h-full">
<div className="flex border-b border-border shrink-0">
<button
onClick={() => setActiveTab('left')}
className={cn(
'flex-1 py-2 text-sm font-medium transition-colors',
activeTab === 'left'
? 'border-b-2 border-primary text-primary'
: 'text-muted-foreground hover:text-foreground'
)}
>
Backlog
</button>
<button
onClick={() => setActiveTab('right')}
className={cn(
'flex-1 py-2 text-sm font-medium transition-colors',
activeTab === 'right'
? 'border-b-2 border-primary text-primary'
: 'text-muted-foreground hover:text-foreground'
)}
>
Stories
</button>
{panes.map((_, i) => (
<button
key={i}
onClick={() => setActiveTab(i)}
className={cn(
'flex-1 py-2 text-sm font-medium transition-colors',
activeTab === i
? 'border-b-2 border-primary text-primary'
: 'text-muted-foreground hover:text-foreground'
)}
>
{tabLabels?.[i] ?? `Pane ${i + 1}`}
</button>
))}
</div>
<div className="flex-1 overflow-auto">
{activeTab === 'left' ? left : right}
{panes[activeTab]}
</div>
</div>
)
@ -110,24 +138,25 @@ export function SplitPane({
return (
<div ref={containerRef} className="flex h-full overflow-hidden select-none">
{/* Left pane */}
<div className="flex flex-col overflow-hidden" style={{ width: `${split}%` }}>
{left}
</div>
{/* Divider */}
<div
onMouseDown={() => setIsDragging(true)}
className={cn(
'w-1 shrink-0 bg-border hover:bg-primary transition-colors cursor-col-resize',
isDragging && 'bg-primary'
)}
/>
{/* Right pane */}
<div className="flex flex-col overflow-hidden flex-1">
{right}
</div>
{panes.map((pane, i) => (
<Fragment key={i}>
{i > 0 && (
<div
onMouseDown={() => setDragging(i - 1)}
className={cn(
'w-1 shrink-0 bg-border hover:bg-primary transition-colors cursor-col-resize',
dragging === i - 1 && 'bg-primary'
)}
/>
)}
<div
className="flex flex-col overflow-hidden"
style={i === n - 1 ? { flex: 1 } : { width: `${splits[i]}%` }}
>
{pane}
</div>
</Fragment>
))}
</div>
)
}

View file

@ -1,137 +0,0 @@
'use client'
import { useRef, useState, useEffect, useCallback } from 'react'
import { cn } from '@/lib/utils'
interface TriplePaneProps {
left: React.ReactNode
middle: React.ReactNode
right: React.ReactNode
storageKey: string
defaultLeft?: number // % width for left pane
defaultMiddle?: number // % width for middle pane, right gets the rest
minSize?: number // minimum px per pane
}
export function TriplePane({
left, middle, right, storageKey,
defaultLeft = 28, defaultMiddle = 35, minSize = 180,
}: TriplePaneProps) {
const containerRef = useRef<HTMLDivElement>(null)
const load = (key: string, def: number) => {
if (typeof window === 'undefined') return def
const stored = localStorage.getItem(`triple-pane:${storageKey}:${key}`)
if (stored) {
const val = parseFloat(stored)
if (!isNaN(val) && val > 0 && val < 100) return val
}
return def
}
const [leftPct, setLeftPct] = useState(() => load('left', defaultLeft))
const [midPct, setMidPct] = useState(() => load('mid', defaultMiddle))
const [dragging, setDragging] = useState<'left' | 'right' | null>(null)
const [isMobile, setIsMobile] = useState(false)
const [activeTab, setActiveTab] = useState<'left' | 'middle' | 'right'>('left')
useEffect(() => {
const check = () => setIsMobile(window.innerWidth < 1024)
check()
window.addEventListener('resize', check)
return () => window.removeEventListener('resize', check)
}, [])
const onMouseMove = useCallback((e: MouseEvent) => {
if (!dragging || !containerRef.current) return
const rect = containerRef.current.getBoundingClientRect()
const width = rect.width
const minPct = (minSize / width) * 100
const offsetPct = ((e.clientX - rect.left) / width) * 100
if (dragging === 'left') {
const clamped = Math.min(Math.max(offsetPct, minPct), 100 - midPct - minPct)
setLeftPct(clamped)
localStorage.setItem(`triple-pane:${storageKey}:left`, String(clamped))
} else {
const clamped = Math.min(Math.max(offsetPct - leftPct, minPct), 100 - leftPct - minPct)
setMidPct(clamped)
localStorage.setItem(`triple-pane:${storageKey}:mid`, String(clamped))
}
}, [dragging, leftPct, midPct, minSize, storageKey])
const onMouseUp = useCallback(() => setDragging(null), [])
useEffect(() => {
if (dragging) {
window.addEventListener('mousemove', onMouseMove)
window.addEventListener('mouseup', onMouseUp)
}
return () => {
window.removeEventListener('mousemove', onMouseMove)
window.removeEventListener('mouseup', onMouseUp)
}
}, [dragging, onMouseMove, onMouseUp])
if (isMobile) {
const tabs = ['left', 'middle', 'right'] as const
const labels = ['Backlog', 'Sprint', 'Taken']
return (
<div className="flex flex-col h-full">
<div className="flex border-b border-border shrink-0">
{tabs.map((tab, i) => (
<button
key={tab}
onClick={() => setActiveTab(tab)}
className={cn(
'flex-1 py-2 text-xs font-medium transition-colors',
activeTab === tab
? 'border-b-2 border-primary text-primary'
: 'text-muted-foreground hover:text-foreground'
)}
>
{labels[i]}
</button>
))}
</div>
<div className="flex-1 overflow-auto">
{activeTab === 'left' ? left : activeTab === 'middle' ? middle : right}
</div>
</div>
)
}
const rightPct = 100 - leftPct - midPct
return (
<div ref={containerRef} className="flex h-full overflow-hidden select-none">
<div className="flex flex-col overflow-hidden" style={{ width: `${leftPct}%` }}>
{left}
</div>
<div
onMouseDown={() => setDragging('left')}
className={cn(
'w-1 shrink-0 bg-border hover:bg-primary transition-colors cursor-col-resize',
dragging === 'left' && 'bg-primary'
)}
/>
<div className="flex flex-col overflow-hidden" style={{ width: `${midPct}%` }}>
{middle}
</div>
<div
onMouseDown={() => setDragging('right')}
className={cn(
'w-1 shrink-0 bg-border hover:bg-primary transition-colors cursor-col-resize',
dragging === 'right' && 'bg-primary'
)}
/>
<div className="flex flex-col overflow-hidden" style={{ width: `${rightPct}%` }}>
{right}
</div>
</div>
)
}