spyne/src/spyne/utils/deep-merge.js

Reactive Real-DOM Framework for Advanced Javascript applications

function isMergeableObject(val) {
  const nonNullObject = val && typeof val === 'object'
  return nonNullObject && Object.prototype.toString.call(val) !== '[object RegExp]' && Object.prototype.toString.call(val) !== '[object Date]'
}

function emptyTarget(val) {
  return Array.isArray(val) ? [] : {}
}

function cloneIfNecessary(value, optionsArgument) {
  const clone = optionsArgument && optionsArgument.clone === true
  return (clone && isMergeableObject(value))
    ? deepMerge(emptyTarget(value),
      value, optionsArgument)
    : value
}

function defaultArrayMerge(target, source, optionsArgument) {
  const destination = target.slice()
  source.forEach(function(e, i) {
    if (typeof destination[i] === 'undefined') {
      destination[i] = cloneIfNecessary(e, optionsArgument)
    } else if (isMergeableObject(e)) {
      destination[i] = deepMerge(target[i], e, optionsArgument)
    } else if (target.indexOf(e) === -1) {
      destination.push(cloneIfNecessary(e, optionsArgument))
    }
  })
  return destination
}

function mergeObject(target, source, optionsArgument) {
  const destination = {}
  if (isMergeableObject(target)) {
    Object.keys(target).forEach(function(key) {
      destination[key] = cloneIfNecessary(target[key], optionsArgument)
    })
  }
  Object.keys(source).forEach(function(key) {
    if (!isMergeableObject(source[key]) || !target[key]) {
      destination[key] = cloneIfNecessary(source[key], optionsArgument)
    } else {
      destination[key] = deepMerge(target[key], source[key], optionsArgument)
    }
  })
  return destination
}

function deepMerge(target, source, optionsArgument) {
  const array = Array.isArray(source)
  const options = optionsArgument || { arrayMerge: defaultArrayMerge }
  const arrayMerge = options.arrayMerge || defaultArrayMerge

  if (array) {
    return Array.isArray(target)
      ? arrayMerge(target, source, optionsArgument)
      : cloneIfNecessary(source, optionsArgument)
  } else {
    return mergeObject(target, source, optionsArgument)
  }
}

deepMerge.all = function deepmergeAll(array, optionsArgument) {
  if (!Array.isArray(array) || array.length < 2) {
    throw new Error(
      'first argument should be an array with at least two elements')
  }

  // we are sure there are at least 2 values, so it is safe to have no initial value
  return array.reduce(function(prev, next) {
    return deepMerge(prev, next, optionsArgument)
  })
}

export { deepMerge }