hashCodeObject

This package is used to set hashCode property to a object.

Install

``
npm install --save hashcodeobject
`

Usage

`
import { defineDeepHashCodeObject } from 'hashcodeobject'

var obj = { a: { b: 10 } }
defineDeepHashCodeObject(obj)

console.log(obj.hashCode)
console.log(obj.a.hashCode)
`

API

$3

Get hash code from a given object/array.

`
import { getObjectHashCode } from 'hashcodeobject'
let hashCode = getObjectHashCode({ a: [ 1, 3, 4 ] })
`

$3

Use defineProperty to set a new property to the given object/array, so that you can use obj.hashCode to get hash code.

Hash code is cached on obj._hashCodeCache, the first time you call obj.hashCode, caculation will be run, but the second time, cache will be used.

If you change a property of this object, cache will be clear, caculation will be run again the next time you call obj.hashCode.

$3

defineObjectHashCodeProperty listen to the top level properties, however, some objects have children in which there are objects too. For example:

`
var obj = {
x: 1,
children: {
y: 2,
},
}
`

This is not fit to use defineObjectHashCodeProperty, it is better to use createHashCodeObject.

`
import { createHashCodeObject } from 'hashcodeobject'
createHashCodeObject(obj)
obj.children.y = 3 // obj.hashCode changed
`

$3

All of above methods do not support objects that has circle structure, i.e.

`
let a = { x: 1 }
let b = { y: 1, a }
a.b = b
`

Here a.b === b, and b.a === a, it is not possible to use JSON.stringify.

To resolve this problem, you'd better to use getComplexObjectHashCode to get hash code here:

`
import { getComplexObjectHashCode } from 'hashcodeobject'
let hash = getComplexObjectHashCode(a)
console.log(hash)
``

However, it is not recommend to use circle structed object to caculate hash code. So I do not provide defineComplexHashCodeObject.