Function baseMergeDeep

test/babel.js:51805–51856

* A specialized version of `baseMerge` for arrays and objects which performs * deep merges and tracks traversed objects enabling objects with circular * references to be merged. * * @private * @param {Object} object The destination object. * @param {Object} source The source object. *

(object, source, key, srcIndex, mergeFunc, customizer, stack)

	 *  counterparts.
	 */
	function baseMergeDeep(object, source, key, srcIndex, mergeFunc, customizer, stack) {
	  var objValue = object[key],
	      srcValue = source[key],
	      stacked = stack.get(srcValue);

	  if (stacked) {
	    assignMergeValue(object, key, stacked);
	    return;
	  }
	  var newValue = customizer ? customizer(objValue, srcValue, key + '', object, source, stack) : undefined;

	  var isCommon = newValue === undefined;

	  if (isCommon) {
	    var isArr = isArray(srcValue),
	        isBuff = !isArr && isBuffer(srcValue),
	        isTyped = !isArr && !isBuff && isTypedArray(srcValue);

	    newValue = srcValue;
	    if (isArr || isBuff || isTyped) {
	      if (isArray(objValue)) {
	        newValue = objValue;
	      } else if (isArrayLikeObject(objValue)) {
	        newValue = copyArray(objValue);
	      } else if (isBuff) {
	        isCommon = false;
	        newValue = cloneBuffer(srcValue, true);
	      } else if (isTyped) {
	        isCommon = false;
	        newValue = cloneTypedArray(srcValue, true);
	      } else {
	        newValue = [];
	      }
	    } else if (isPlainObject(srcValue) || isArguments(srcValue)) {
	      newValue = objValue;
	      if (isArguments(objValue)) {
	        newValue = toPlainObject(objValue);
	      } else if (!isObject(objValue) || srcIndex && isFunction(objValue)) {
	        newValue = initCloneObject(srcValue);
	      }
	    } else {
	      isCommon = false;
	    }
	  }
	  if (isCommon) {
	    // Recursively merge objects and arrays (susceptible to call stack limits).
	    stack.set(srcValue, newValue);
	    mergeFunc(newValue, srcValue, srcIndex, customizer, stack);
	    stack['delete'](srcValue);
	  }
	  assignMergeValue(object, key, newValue);
	}

	module.exports = baseMergeDeep;