Core concepts

Terminology and data flow for @jayoncode/object-diff.

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Problem → approach

Manual comparison	With Object Diff
JSON.stringify(a) !== JSON.stringify(b) — no paths, false positives on key order	diff(a, b) — typed change records with paths
Hand-rolled patch objects for every API	patch(result) — RFC 6902 operations from any diff
Full re-send of large state on every edit	applyPatch(target, ops) — minimal updates
Custom formatters for audit UIs	serialize(result, "markdown" | "json" | …)

Snapshots and change records

const before = { user: { name: "John" }, count: 1 };
const after = { user: { name: "Jane" }, count: 1 };

const result = diff(before, after);
// result.changes[] — path, type (add|update|remove), value, oldValue

API map

API	Returns	Use when
diff(a, b)	Change records + metadata	Audit, debug, UI diff viewers
hasChanges(a, b)	boolean	Dirty flags, skip expensive work
compare(a, b)	Equality + path detail	Tests
patch(diffResult)	JSON Patch ops	Network sync, undo stacks
applyPatch(target, ops)	New object	Apply remote or local updates
serialize(result, format)	String	Logs, exports, docs

Change record fields

Field	Meaning
path	Dot/bracket path (e.g. user.name)
type	update, add, or remove
value	Value after change
oldValue	Value before change (updates/removes)

Next steps

Goal	Guide
First integration	Tutorial
Diff options	Diffing
Patch apply/revert	Patching

Diff explorer →