@stopcock/diff

Structural diffing and patching. Compute patches between objects, apply them, compose them, invert them, rebase concurrent edits.

bun add @stopcock/diff

import { diff, apply, invert, compose, rebase } from '@stopcock/diff'

const before = { name: 'Tom', scores: [10, 20] }
const after = { name: 'Tom', scores: [10, 20, 30] }

const p = diff(before, after)
apply(before, p) // { name: 'Tom', scores: [10, 20, 30] }

const undo = invert(p)
apply(after, undo) // back to before

What's in the box

• diff / diffWith — compute a Patch between two values, with optional move/rename detection and custom equality
• apply / applyUnsafe — apply a patch to a value (safe returns Result, unsafe throws)
• invert — reverse a patch for undo
• compose — merge sequential patches into one, with simplification
• rebase — transform a patch over concurrent edits, with conflict detection
• toJsonPatch / fromJsonPatch — RFC 6902 JSON Patch interop
• toLens / fromLens / fromTraversal — bridge between patches and @stopcock/fp optics

All functions are dual (data-first and data-last).