ds-algo-study/DS-n-Algos/functions/HASH/HASH.js

Just experimenting with publishing a package

/**
 * utilities for hashing config objects.
 * basically iteratively updates hash with a JSON-like format
 */

'use strict'
exports.__esModule = true

const doHash = require('crypto').createHash



function hashEntity(value, hash) {
  if (!hash) hash = doHash('sha256')

  if (value instanceof Array) {
    hshArr(value, hash)
  } else if (value instanceof Object) {
    hshObj(value, hash)
  } else {
    hash.update( stringify( value ) || 'undefined' );
  }

  return hash
}


function hshArr(array, hash) {
  if (!hash) hash = doHash('sha256')

  hash.update('[')
  for (let i = 0; i < array.length; i++) {
    hashEntity(array[i], hash)
    hash.update(',')
  }
  hash.update(']')

  return hash
}
hashEntity.array = hshArr

function hshObj(object, hash) {
  if (!hash) hash = doHash('sha256')

  hash.update('{')
  Object.keys(object).sort().forEach(key => {
    hash.update(JSON.stringify((key)))
    hash.update(':')
    hashEntity(object[key], hash)
    hash.update(',')
  })
  hash.update('}')

  return hash
}
hashEntity.object = hshObj