Benchmark: Object.assign vs spread operator vs foreach set 2

Tests:

Object.assign
var params = { b:"hello", c: true, d:7 }; var old = {a: 2, b: "somthing"}; var other = Object.assign(old, params);
spread operator
var params = { b:"hello", c: true, d:7 }; var old = {a: 2, b: "somthing"}; var other = { ...old , ...params };
foreach
var params = [ ["b", "hello"], ["c", true], ["d", 7] ]; var other = {a: 2, b: "somthing"}; params.forEach(style => { other[style[0]] = style[1]; });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.assign
spread operator
foreach

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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Let's break down the provided benchmark and its test cases to understand what is being tested.

**Benchmark Definition Json**

The provided `benchmark.json` file defines a benchmark with three test cases:

* Name: "Object.assign vs spread operator vs foreach set 2"
* Description: None
* Script Preparation Code: None
* Html Preparation Code: None

This means that the user has created a benchmark to compare the performance of three different approaches for merging objects in JavaScript:

1. `Object.assign()`
2. Spread operator (`{ ... }`)
3. `forEach` loop with object iteration.

**Test Cases**

There are three test cases:

### Test Case 1: Object.assign()

```javascript
var params = { b:"hello", c: true, d:7 };
var old = {a: 2, b: "somthing"};
var other = Object.assign(old, params);
```

This test case creates an object `old` with a single property `b` and another object `params` with three properties (`b`, `c`, and `d`). The `Object.assign()` method is used to merge the two objects into a new object `other`.

### Test Case 2: Spread Operator

```javascript
var params = { b:"hello", c: true, d:7 };
var old = {a: 2, b: "somthing"};
var other = { ...old , ...params };
```

This test case is similar to the previous one, but instead of using `Object.assign()`, it uses the spread operator (`{ ... }`) to merge the two objects into a new object `other`.

### Test Case 3: foreach

```javascript
var params = [ ["b", "hello"], ["c", true], ["d", 7] ];
var other = {a: 2, b: "somthing"};
params.forEach(style => {
    other[style[0]] = style[1];
});
```

This test case uses a `forEach` loop to iterate over an array of arrays (`params`) and merge each inner array into the object `other`. The resulting properties are assigned to the corresponding keys in the `other` object.

**Options Compared**

The three approaches are compared for their performance:

* `Object.assign()`: a built-in JavaScript method for merging objects
* Spread operator (`{ ... }`): a new syntax introduced in ECMAScript 2015 for spreading arrays and objects into a new object
* `forEach` loop with object iteration: a more traditional approach using a loop to iterate over the object's properties

**Pros and Cons**

Here are some pros and cons of each approach:

* `Object.assign()`: Pros:
	+ Efficient and widely supported
	+ Can handle nested objects
	Contras:
	+ May not be as readable or intuitive for some developers
* Spread operator (`{ ... }`): Pros:
	+ More concise and readable than traditional loops
	+ Allows for easier merging of objects with similar keys
Contras:
	+ May not work correctly if the source object has non-enumerable properties
	+ Requires support for ECMAScript 2015 or later
* `forEach` loop with object iteration: Pros:
	+ Can handle any type of property (enumerable, non-enumerable, etc.)
	+ More control over the merging process
Contras:
	+ May be slower and more verbose than other approaches

**Library Used**

None.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax used in this benchmark. The `forEach` loop is a standard feature, but it's not specific to any particular language version.

**Other Alternatives**

Other alternatives for merging objects could include:

* Using the `Array.prototype.reduce()` method
* Using the `Object.assign()` method with an object literal (e.g., `{ ...other, ...params }`)
* Using a custom function or utility library specifically designed for merging objects

Note that these alternatives may have different performance characteristics and trade-offs compared to the approaches tested in this benchmark.

Related benchmarks:

Object.assign vs spread operator vs foreach set 2 (version: 0)

Comparing performance of: Object.assign vs spread operator vs foreach

Created: 3 years ago by: Guest

Jump to the latest result

Object.assign

spread operator

foreach

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):