Diffcore vs jsondiffpatchfast WASM diff with RFC 6902 Patch

Diffcore runs the diff in Rust compiled to WebAssembly, returns standard RFC 6902 JSON Patch with real RFC 6901 paths, ships applyPatch / revertPatch, a React useDiff hook, a CLI, and a streaming engine for multi-GB files. Benchmarks: 3.3 to 4.1× faster than optimized pure-JS diff. jsondiffpatch is the long-time pure-JS option with a custom delta format.

npm install diffcore

import { diff, applyPatch } from "diffcore";

const before = { user: { name: "Ada", roles: ["admin"] } };
const after  = { user: { name: "Ada", roles: ["admin", "ops"] } };

const patch = diff(before, after);
// [ { op: "add", path: "/user/roles/1", value: "ops" } ]

const next = applyPatch(before, patch);  // { user: { name: "Ada", roles: ["admin", "ops"] } }

• Is Diffcore faster than jsondiffpatch?

  Yes — 3.3 to 4.1× on the same payloads, because the diff itself runs in Rust compiled to WebAssembly. Sustained throughput is 360–490 MB/s. The gap widens on large nested objects.

• Does it emit standard RFC 6902 JSON Patch?

  Yes. Real RFC 6901 paths, decoded values, interoperable with fast-json-patch, jsondiffpatch, and any IETF-compliant consumer.

• Does it have a React hook?

  useDiff returns the JSON Patch and decoded values for two state objects, with automatic memoization.

• Can it handle multi-GB files?

  Yes — the streaming engine diffs without holding both documents in memory.

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