node-object-hash

What is node-object-hash?

The node-object-hash package is a utility for creating consistent hash values from JavaScript objects. It is useful for tasks such as caching, object comparison, and ensuring data integrity.

What are node-object-hash's main functionalities?

Hashing Objects

This feature allows you to create a hash from a JavaScript object. The hash can be used to uniquely identify the object.

const objectHash = require('node-object-hash');
const hasher = objectHash();
const obj = { name: 'John', age: 30 };
const hash = hasher.hash(obj);
console.log(hash);

Custom Hashing Options

This feature allows you to customize the hashing process by specifying options such as coercion and the hashing algorithm.

const objectHash = require('node-object-hash');
const hasher = objectHash({ coerce: true, alg: 'sha256' });
const obj = { name: 'John', age: 30 };
const hash = hasher.hash(obj);
console.log(hash);

Hashing Arrays

This feature allows you to create a hash from an array, ensuring that the array's contents are uniquely identified.

const objectHash = require('node-object-hash');
const hasher = objectHash();
const arr = [1, 2, 3, 4];
const hash = hasher.hash(arr);
console.log(hash);

Other packages similar to node-object-hash

object-hash

The object-hash package is another utility for creating hash values from JavaScript objects. It offers similar functionality to node-object-hash but with a different API and additional features such as support for circular references.

hash-it

The hash-it package provides a simple and fast way to hash JavaScript objects. It is designed to be lightweight and easy to use, making it a good alternative to node-object-hash for basic hashing needs.

crypto

The built-in crypto module in Node.js can also be used to create hash values from objects. While it requires more manual setup compared to node-object-hash, it offers greater flexibility and is part of the standard library.

README

node-object-hash

Node object hash library. Built on top of node's crypto module.

Installation

npm i node-object-hash

Features

• Supports object property sorting for constant hashes for objects with same properties, but different order.
  • NOTE: object arrays should be sorted manually if needed
• Supports ES6 Maps and Sets.
• Supports type coercion (e.g. 1 and "1" will be the same)
  • rules:
    • numbers and strings represented without quotes;
    • boolean values converted to numbers;
• Supports all hashes and encodings of crypto library
• Supports large objects and arrays

API

hash(object[, options])

Returns hash string.

• object object for calculating hash;
• options object with options;
• options.alg hash algorithm (default: 'sha256');
• options.enc hash encoding (default: 'hex');
• options.coerce if true performs type coercion (default: true);
• options.sort if true performs sorting on objects, arrays and Sets (default: true);

sortedObjectString(object[, options])

Returns sorted string generated from object

• object object for calculating hash;
• options object with options;
• options.coerce if true performs type coercion (default: true);
• options.sort if true performs sorting on objects, arrays and Sets (default: true);

Requirements

• >=nodejs-6.0.0

Example

const {hash} = require('node-object-hash');

const object = {
  x: new Map([['a', 1], ['c', 3], ['b', 2]]),
  z: new Set([4,3,2,1]),
  f: 2,
  e: [{a:2}, 3, {g:2, e:{d:1}}, "rt", "1", "2abc", "3d"],
  d: [3,5,6,1,2,3],
  c: "3ab",
  b: "2",
  a: 1
};

const hashString = hash(object);
const hashStringSha512 = hash(object, {alg:'sha512'});

Compared to same libraries

• https://www.npmjs.com/package/object-hash
  • Pros:
    • node-object-hash has twice smaller memory footprint
    • five times faster
    • no memory leak when using in sync flow
  • Cons:
    • Only >=node-6.0.0 supported

License

ISC