rollbar/src/merge.js

Effortlessly track and debug errors in your JavaScript applications with Rollbar. This package includes advanced error tracking features and an intuitive interface to help you identify and fix issues more quickly.

'use strict';

var hasOwn = Object.prototype.hasOwnProperty;
var toStr = Object.prototype.toString;

var isPlainObject = function isPlainObject(obj) {
  if (!obj || toStr.call(obj) !== '[object Object]') {
    return false;
  }

  var hasOwnConstructor = hasOwn.call(obj, 'constructor');
  var hasIsPrototypeOf =
    obj.constructor &&
    obj.constructor.prototype &&
    hasOwn.call(obj.constructor.prototype, 'isPrototypeOf');
  // Not own constructor property must be Object
  if (obj.constructor && !hasOwnConstructor && !hasIsPrototypeOf) {
    return false;
  }

  // Own properties are enumerated firstly, so to speed up,
  // if last one is own, then all properties are own.
  var key;
  for (key in obj) {
    /**/
  }

  return typeof key === 'undefined' || hasOwn.call(obj, key);
};

function merge() {
  var i,
    src,
    copy,
    clone,
    name,
    result = {},
    current = null,
    length = arguments.length;

  for (i = 0; i < length; i++) {
    current = arguments[i];
    if (current == null) {
      continue;
    }

    for (name in current) {
      src = result[name];
      copy = current[name];
      if (result !== copy) {
        if (copy && isPlainObject(copy)) {
          clone = src && isPlainObject(src) ? src : {};
          result[name] = merge(clone, copy);
        } else if (typeof copy !== 'undefined') {
          result[name] = copy;
        }
      }
    }
  }
  return result;
}

module.exports = merge;