The hash-it npm package is a utility for creating unique hash values from JavaScript objects. It is particularly useful for creating hash keys for complex objects, ensuring that the same object will always produce the same hash value.
Hashing Objects
This feature allows you to generate a unique hash value for a given JavaScript object. The same object will always produce the same hash value, which is useful for caching or quick comparisons.
const { hash } = require('hash-it');
const obj = { a: 1, b: 2 };
const hashValue = hash(obj);
console.log(hashValue);Hashing Arrays
This feature allows you to generate a unique hash value for an array. It ensures that the same array will always produce the same hash value, which can be useful for array comparisons or caching.
const { hash } = require('hash-it');
const arr = [1, 2, 3];
const hashValue = hash(arr);
console.log(hashValue);Hashing Nested Structures
This feature allows you to generate a unique hash value for nested structures, including objects within objects and arrays within objects. It ensures consistency in hash values for complex data structures.
const { hash } = require('hash-it');
const nestedObj = { a: { b: 2 }, c: [1, 2, 3] };
const hashValue = hash(nestedObj);
console.log(hashValue);The object-hash package provides similar functionality to hash-it by generating unique hash values for JavaScript objects. It supports a variety of hashing algorithms and can handle complex nested structures. Compared to hash-it, object-hash offers more customization options for the hashing process.
The hasha package is a versatile hashing utility that supports multiple hashing algorithms like MD5, SHA-1, and SHA-256. While it is not specifically designed for hashing objects, it can be used to hash strings, buffers, and other data types. It is more general-purpose compared to hash-it.
The built-in Node.js crypto module provides a wide range of cryptographic functionalities, including hashing. While it is more complex and requires more setup to hash objects compared to hash-it, it offers extensive options for cryptographic operations and is highly customizable.
Fast and consistent hashCode for any object type
// ES2015
import hashIt from 'hash-it';
// CommonJS
const hashIt = require('hash-it').default;
// script
const hashIt = window.hashIt;
// hash any standard object
console.log(hashIt({foo: 'bar'})); // 2639617176
// or if you know it is a circular object
console.log(hashIt(window, true)); // 482488043
hashIt has a simple goal: provide a fast and consistent hashCode for any object type that is uniquely based on its values. This has a number of uses such as duplication prevention or fast equality comparisons.
Any object type?
Yes, any object type. Primitives, ES2015 classes like Symbol, DOM elements (yes, you can even hash the window object if you want). Any object type.
With no exceptions?
Well ... sadly, no, there are a few exceptions.
Promise
Generator (the result of calling a GeneratorFunction)
Promise, there is no way to obtain the values contained within due to its dynamic iterable natureWeakMap / WeakSet
In each of these cases, no matter what the values of the object, they will always yield the same hash result, which is unique to each object type. If you have any ideas about how these can be uniquely hashed, I welcome them!
Here is the list of object classes that have been tested and shown to produce unique hashCodes:
ArgumentsArrayArrayBufferBooleanDataViewDate (based on valueOf)Error (based on message)
TypeError, ReferenceError, etc.)Float32ArrayFloat64ArrayFunction (based on toString)GeneratorFunction (based on toString)Int8ArrayInt16ArrayInt32ArrayHTMLElement (based on tagName, attributes, and innerHTML)
HTMLAnchorElement, HTMLDivElement, etc.)MapMath (based on E, LN2, LN10, LOG2E, LOG10E, PI, SQRT1_2, and SQRT2)NullNumberObject (can handle circular objects)ProxyRegExpSetStringSymbolUint8ArrayUint8ClampedArrayUint16ArrayUint32ArrayUndefinedWindowThis is basically all I could think of, but if I have missed an object class let me know and I will add it!
isEmpty(object: any): boolean
Determines if object is empty based on hashCode, with empty defined as:
[])new Map())0){})new Set())'')undefined)null)This differs from the implementation by lodash, where a value is considered not empty if an Array, Object, Map, or Set. Think of this definition of empty as "having no value(s)".
isEqual(object1: any, object2: any[, object3: any[, ...objectN]]): boolean
Compares all objects passed to it to determine if they are equal to one another based on hashCode
const foo = {
foo: 'bar'
};
const alsoFoo = {
foo: 'bar'
};
console.log(foo === alsoFoo); // false
console.log(hashIt.isEqual(foo, alsoFoo)); // true
isNull(object: any): boolean
Determines if object is null based on hashCode
isUndefined(object: any): boolean
Determines if object is undefined based on hashCode
While the hashes will be consistent when calculated within the same browser environment, there is no guarantee that the hashCode will be the same across different browsers due to browser-specific implementations of features. A vast majority of the time things line up, but there are some edge cases that can cause differences, so just something to be mindful of.
Standard stuff, clone the repo and npm install dependencies. The npm scripts available:
build => run webpack to build development dist file with NODE_ENV=developmentbuild:minified => run webpack to build production dist file with NODE_ENV=productiondev => run webpack dev server to run example app / playgrounddist => runs build and build:minifiedlint => run ESLint against all files in the src folderprepublish => runs prepublish:compile when publishingprepublish:compile => run lint, test:coverage, transpile:es, transpile:lib, disttest => run AVA test functions with NODE_ENV=testtest:coverage => run test but with nyc for coverage checkertest:watch => run test, but with persistent watchertranspile:lib => run babel against all files in src to create files in libtranspile:es => run babel against all files in src to create files in es, preserving ES2015 modules (for
pkg.module)3.1.1
FAQs
Hash any object based on its value
The npm package hash-it receives a total of 248,181 weekly downloads. As such, hash-it popularity was classified as popular.
We found that hash-it demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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