ohash

#️ ohash

Simple object hashing, serialization and comparison utils.

ohash v2 is the current release. For the previous API, see the v1 branch and the v2.0.1 release notes for migration.

Usage

Install ohash:

# ✨ Auto-detect (npm, yarn, pnpm, bun or deno)
npx nypm i ohash

Import:

// ESM import
import { hash, serialize, digest, isEqual } from "ohash";
import { diff } from "ohash/utils";

// Dynamic import
const { hash, serialize, digest, isEqual } = await import("ohash");
const { diff } = await import("ohash/utils");

import { hash, serialize, digest, isEqual } from "https://esm.sh/ohash";
import { diff } from "https://esm.sh/ohash/utils";

// Dynamic import
const { hash, serialize, digest, isEqual } = await import(
  "https://esm.sh/ohash"
);
const { diff } = await import("https://esm.sh/ohash/utils");

hash(input)

Hashes any JS value into a string.

The input is first serialized then it is hashed.

import { hash } from "ohash";

// "g82Nh7Lh3CURFX9zCBhc5xgU0K7L0V1qkoHyRsKNqA4"
console.log(hash({ foo: "bar" }));

serialize(input)

Serializes any input value into a string for hashing.

serialize method uses best efforts to generate stable serialized values; however, it is not designed for security purposes. Keep in mind that there is always a chance of intentional collisions caused by user input.

import { serialize } from "ohash";

// "{foo:'bar'}"
console.log(serialize({ foo: "bar" }));

digest(str)

Hashes a string using the SHA-256 algorithm and encodes it in Base64URL format.

import { digest } from "ohash";

// "f4OxZX_x_FO5LcGBSKHWXfwtSx-j1ncoSt3SABJtkGk"
console.log(digest("Hello World!"));

isEqual(obj1, obj2)

Compare two objects using === and then fallbacks to compare based on their serialized values.

import { isEqual } from "ohash";

// true
console.log(isEqual({ a: 1, b: 2 }, { b: 2, a: 1 }));

diff(obj1, obj2)

Compare two objects with nested serialization. Returns an array of changes.

The returned value is an array of diff entries with $key, $hash, $value, and $props. When logging, a string version of the changelog is displayed.

import { diff } from "ohash/utils";

const createObject = () => ({
  foo: "bar",
  nested: {
    y: 123,
    bar: {
      baz: "123",
    },
  },
});

const obj1 = createObject();
const obj2 = createObject();

obj2.nested.x = 123;
delete obj2.nested.y;
obj2.nested.bar.baz = 123;

const changes = diff(obj1, obj2);

// Removed `nested.y`
// Changed `nested.bar.baz` from `"123"` to `123`
// Added   `nested.x`
console.log(changes.join("\n"));

Contribute

• Clone this repository
• Enable Corepack using corepack enable
• Install dependencies using pnpm install
• Run interactive tests using pnpm dev

License

Made with Published under MIT License.

Object serialization originally based on puleos/object-hash by Scott Puleo.

sha256 implementation originally based on brix/crypto-js.

Migration from v1

There is no v2 helper that reproduces the exact v1 objectHash string format. Use serialize when you need a stable structural string, and hash when you need a short digest.