skellla / node-object-hash Goto Github PK

I would like to hash my arrays hashed depending on their order, but objects and sets are unordered, so want them sorted before hash. Yet currently "sort" is a global option....

Possible solutions:

1. On initialization, "sortFilter" option that takes a predicate which should return true if given object should be sorted before hash.
2. per-hash, pass "sort" option, which could be explicitly true or false to override global, or not-present/null to accept default.

EDIT -- In fact, if (2) is to be viable, it should take "sortFilter" as well, so that subobjects can be taken care of properly.

microsoft/vscode#87268 🎅

Merry Christmas!

This lib seems great! It's exactly what I need as well
Is there a chance to have it compatible with node 4.3?
What part of it is dependent on node 6.x?

I'd like to be able to disable the sorting of arrays, so that hash([1,2] != hash([2,1]), while keeping all other "object" types sorted. Is this currently possible?

Hi,

Let's suppose that I have following ES6 class:

class ClassA {
  constructor(public propertyA: string) { 
    this.propertyA = propertyA;
  }
}

obj.constructor.name returns 'ClassA' and __guessObjectType() returns 'unknown'

As a result, all different objects of type ClassA return same hash!

I am not sure how to handle this case, naively I would also return 'object' in default handling of switch in guessObjectType()

Hashing fails when there is BigInt type.

> const Hasher = require('node-object-hash')
> const hasher = Hasher()
> hasher.hash(1)
'6b86b273ff34fce19d6b804eff5a3f5747ada4eaa22f1d49c01e52ddb7875b4b'
> hasher.hash(1n)
Uncaught TypeError: stringifiers[typeGuess_1.guessType(...)] is not a function
    at objectToString (***/node_modules/node-object-hash/dist/objectSorter.js:135:56)
    at Object.hashObject [as hash] (***/node_modules/node-object-hash/dist/hasher.js:33:22)

Trying to hash a 256 mb Uint8array crashes the node instance with an out of memory. It appears the base object is just too large to be handled this way. It would be nice to not convert array buffers into strings, but hash them raw.

My tests indicate that Array.from() does not work on WeakMap and WeakSet, so I don't think these should be removed from objectSorter.js

I've tried your module to calculate hash of objects are created via constructor. Although two objects have different property values they hashes are equal. Here is an example:

const assert = require('assert')
const hasher = require('node-object-hash')().hash

class Test {
	constructor(id) {
		this.id = id
	}
}

const t1 = new Test(1)
const t2 = new Test(2)
const h1 = hasher(t1)
const h2 = hasher(t2)

assert.notEqual(h1, h2)

require('node-object-hash')().hash(Object.create(null))

TypeError: Cannot read property 'name' of undefined
    at _guessObjectType (.../node-object-hash/objectSorter.js:20:27)
    at _guessType (.../node-object-hash/objectSorter.js:68:37)
    at objectToString (.../node-object-hash/objectSorter.js:213:24)
    at sortObject (.../node-object-hash/index.js:78:12)
    at Object.hashObject [as hash] (.../node-object-hash/index.js:103:18

Here is the offending line (20):

This assumes that every (non-null) object has as constructor property, which is not generally the case.

sha256 is a cryptographic hash. The most likely use case for a library such as this is object fingerprinting. That doesn't require cryptographic safety. Something like https://github.com/Cyan4973/xxHash would likely be a lot better choice.

I am sorry if this comes off as a dumb question but what are some of examples of what you could use this library to do? I have entertained the idea of hashing my objects into a history tree, similar to git and things like that. I was curious what others actually use this for.