Run results for: Deep merge lodash vs ramda vs deepmerge vs es-toolkit vs deepMergeRightOnPlace

Test name	Executions per second
✓ deepmergeRightOnPlace	7,828,086 Ops/sec
deepMergeRightOnPlace2	4,437,084 Ops/sec
Ramda.mergeDeepRight	2,243,602 Ops/sec
Lodash.merge	1,575,367 Ops/sec
es-toolkit merge	277,473 Ops/sec
deepmerge	90,717 Ops/sec

Script Preparation code:

function isObject(x) { return Object.prototype.toString.call(x) === '[object Object]';}

function deepMergeRightOnPlace(target, source) {
  for (const key in source) {
    if (source.hasOwnProperty(key)) {
      const sourceVal = source[key];
      const targetVal = target[key];

      if (
        isObject(sourceVal) && isObject(targetVal)
      ) {
        // Рекурсивное объединение вложенных объектов
        deepMergeRightOnPlace(targetVal, sourceVal);
      } else {
        // Перезапись значения
        target[key] = sourceVal;
      }
    }
  }

  return target;
}

function deepMergeRightOnPlace2(ref, source) {
  const keys = Object.keys(source);
  for (let i = 0; i < keys.length; i += 1) {
    const key = keys[i];

    if (source.hasOwnProperty(key)) {
      const sourceVal = source[key];
      const targetVal = ref[key];

      if (isObject(sourceVal) && isObject(targetVal)) {
        deepMergeRightOnPlace(targetVal, sourceVal);
      } else {
        ref[key] = sourceVal;
      }
    }
  }
};

var obj1 = {
		"a": "0001",
		"b": "donut",
		"c": "Cake",
		"d": 0.55,
		"e":
			{
				"ea":
					[
						{ "id": "1001", "type": "Regular" },
						{ "id": "1002", "type": "Chocolate" },
						{ "id": "1003", "type": "Blueberry" },
						{ "id": "1004", "type": "Devil's Food" }
					]
			},
		"f":
			[
				{ "id": "5001", "type": "None" },
				{ "id": "5002", "type": "Glazed" },
				{ "id": "5005", "type": "Sugar" },
				{ "id": "5007", "type": "Powdered Sugar" },
				{ "id": "5006", "type": "Chocolate with Sprinkles" },
				{ "id": "5003", "type": "Chocolate" },
				{ "id": "5004", "type": "Maple" }
			]
	};

var obj2 = 
	{
		"a": "0003",
		"b": "Overwritten",
		"c": "Old Fashioned",
		"d": 0.55,
		"e":
			{
				"ea":
					[
						{ "id": "1001", "type": "Overwritten" },
						{ "id": "1002", "type": "Chocolate" }
					]
			},
		"f":
			[
				{ "id": "5001", "type": "None" },
				{ "id": "5002", "type": "Glazed" },
				{ "id": "5003", "type": "Chocolate" },
				{ "id": "5004", "type": "Maple" }
			]
	};

Run results for: Deep merge lodash vs ramda vs deepmerge vs es-toolkit vs deepMergeRightOnPlace

Ramda.mergeDeepRight

Lodash.merge

deepmerge

es-toolkit merge

deepmergeRightOnPlace

deepMergeRightOnPlace2