Object Comparator

objectComparator.js

const objectComparator = (a, b) => {
  if (a === b) {
    return {
      changed: 'equal',
      value: a
    }
  }

  var value = {}
  var equal = true

  for (var key in a) {
    if (key in b) {
      if (a[key] === b[key]) {
        value[key] = {
          changed: 'equal',
          value: a[key]
        }
      } else {
        var typeA = typeof a[key]
        var typeB = typeof b[key]
        if (a[key] && b[key] && (typeA == 'object' || typeA == 'function') && (typeB == 'object' || typeB == 'function')) {
          var valueDiff = objectComparator(a[key], b[key])
          if (valueDiff.changed == 'equal') {
            value[key] = {
              changed: 'equal',
              value: a[key]
            }
          } else {
            equal = false
            value[key] = valueDiff
          }
        } else {
          equal = false
          value[key] = {
            changed: 'primitive change',
            removed: a[key],
            added: b[key]
          }
        }
      }
    } else {
      equal = false
      value[key] = {
        changed: 'removed',
        value: a[key]
      }
    }
  }

  for (key in b) {
    if (!(key in a)) {
      equal = false
      value[key] = {
        changed: 'added',
        value: b[key]
      }
    }
  }

  if (equal) {
    return {
      changed: 'equal',
      value: a
    }
  } else {
    return {
      changed: 'object change',
      value: value
    }
  }
}