Benchmark: Merge array of objects with an object.

Script Preparation code:

var obj = { ...[...Array(10).keys()] };
var arrOfObjs = [];
var obj1 = Array(5).fill(0).map((_, idx) => idx + 5).reduce((acc, val) => {  acc[val] = val;
  return acc;
}, {});
var obj2 = Array(5).fill(0).map((_, idx) => idx + 10).reduce((acc, val) => {acc[val] = val;
  return acc;
}, {});
var obj3 = Array(5).fill(0).map((_, idx) => idx + 15).reduce((acc, val) => {  acc[val] = val;
  return acc;
}, {});
var obj4 = Array(5).fill(0).map((_, idx) => idx + 20).reduce((acc, val) => {  acc[val] = val;
  return acc;
}, {});
arrOfObjs.push(obj1, obj2, obj3, obj4);

Tests:

assign
var result = Object.assign(obj, ...arrOfObjs);
reduce with spread operator
var result = arrOfObjs.reduce((acc, val) => ({ ...acc, ...val }), obj);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
assign
reduce with spread operator

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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**Benchmark Definition**

The benchmark is designed to measure the performance of JavaScript functions that merge an array of objects with a single object using two different approaches:

1. `Object.assign()`: This method takes multiple source objects as arguments and merges them into a new object.
2. `Array.prototype.reduce()` with the spread operator (`...`): This method applies a reduction function to each element in an array, accumulating a result.

**Test Cases**

There are two individual test cases:

1. **assign**: This test case uses `Object.assign()` to merge `obj` (a single object created using array indices) with the merged objects from `arrOfObjs`.
2. **reduce with spread operator**: This test case uses `Array.prototype.reduce()` with the spread operator (`...`) to merge `obj` with the merged objects from `arrOfObjs`.

**Options Compared**

The benchmark compares two different approaches:

* `Object.assign()`
* `Array.prototype.reduce()` with the spread operator (`...`)

**Pros and Cons of Each Approach**

1. **Object.assign()**:
	* Pros:
		+ Concise and easy to read.
		+ Works well for simple merges.
	* Cons:
		+ Can be slower due to the overhead of function calls.
		+ May not perform as well on large arrays or complex objects.
2. **Array.prototype.reduce()` with spread operator (`...`):
	* Pros:
		+ More flexible and powerful, allowing for more complex merging operations.
		+ Can be faster for larger arrays or more complex data structures.
	* Cons:
		+ May be less readable due to the use of an accumulator function.

**Library and Purpose**

The `Array.prototype.reduce()` method is a built-in JavaScript method that applies a reduction function to each element in an array, accumulating a result. The spread operator (`...`) is used to expand the elements of an array into separate arguments for the reduction function.

**Special JS Feature or Syntax**

There are no special features or syntaxes mentioned in this benchmark.

**Other Alternatives**

If you were to implement this benchmark from scratch, other alternatives could include:

* Using `Object.merge()` or a similar library that provides a merge function.
* Implementing a custom merge function using recursion or iteration.
* Using a different data structure, such as a map or an object with nested objects.

Keep in mind that these alternatives would likely have different performance characteristics and trade-offs compared to the original approaches.

Related benchmarks:

Merge array of objects with an object. (version: 0)

Comparing performance of: assign vs reduce with spread operator

Created: 5 years ago by: Guest

Jump to the latest result

assign

reduce with spread operator

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):