node-object-hash

Node.js object hash library with properties/arrays sorting to provide constant hashes.

Built on top of node's crypto module (so for using in browser use something like browserify or use crypto functions polyfills).

Installation

npm i node-object-hash

Features

• Supports object property sorting for constant hashes for objects with same properties, but different order.
• Supports ES6 (Weak)Maps and (Weak)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

Changes

v0.x.x -> v1.0.0

• Sorting mechanism rewritten form ES6 Maps to simple arrays (add <=node-4.0.0 support)
• Performance optimization (~2 times faster than 0.x.x)
• API changes:
  • Now module returns 'constructor' function, where you can set default parameters: var objectHash = require('node-object-hash')(options);

In case if you still need an old 0.x.x version it's available in hash.js file.

API

Constructor require('node-object-hash')([options])

Returns preconfigured object with API

Parameters:

• options:<object> - object with hasher config options
• options.coerce:<boolean> - if true performs type coercion (default: true); e.g. hash(true) == hash('1') == hash(1), hash(false) == hash('0') == hash(0)
• options.sort:<boolean> - if true performs sorting on objects, arrays, etc. (default: true);
• options.alg:<string> - sets default hash algorithm (default: 'sha256'); can be overridden in hash method;
• options.enc:<string> - sets default hash encoding (default: 'hex'); can be overridden in hash method;

hash(object[, options])

Returns hash string.

• object:<*> object for calculating hash;
• options:<object> object with options;
• options.alg:<string> - hash algorithm (default: 'sha256');
• options.enc:<string> - hash encoding (default: 'hex');

sortObject(object)

Returns sorted string generated from object

• object:<*> - object for sorting;

Requirements

version >=1.0.0

• >=nodejs-0.10.0

version >=0.1.0 && <1.0.0

• >=nodejs-6.0.0
• >=nodejs-4.0.0 (requires to run node with --harmony flag)

browsers

• nodejs crypto module (for browsers)

Example

var hasher = require('node-object-hash');

var hashSortCoerce = hasher({sort:true, coerce:true});
// or
// var hashSortCoerce = hasher();
// or
// var hashSort = hasher({sort:true, coerce:false});
// or
// var hashCoerce = hasher({sort:false, coerce:true});

var objects = {
    a: {
      a: [{c: 2, a: 1, b: {a: 3, c: 2, b: 0}}],
      b: [1, 'a', {}, null],
    },
    b: {
      b: ['a', 1, {}, undefined],
      a: [{c: '2', b: {b: false, c: 2, a: '3'}, a: true}]
    },
    c: ['4', true, 0, 2, 3]
};

hashSortCoerce.hash(objects.a) === hashSortCoerce.hash(objects.b);
// returns true

hashSortCoerce.sortObject(object.c)
// returns '[0,1,2,3,4]'

Benchmark results

Bench data - array of 100000 complex objects

Usage

npm run bench

Results

Similar libraries

• https://www.npmjs.com/package/object-hash (Slow, but browser-ready and most js types supported)
• https://www.npmjs.com/package/hash-object (no ES6 types support)

License

ISC