Benchmark: test spread and assign

Tests:

test1
for(var i = 0; i <= 100000; i++) { const a = { a: 'a', b: 'b'}; const b = { c: 'c' } const c = { ...a, ...b } }
test2
for(var i = 0; i <= 100000; i++) { const a = { a: 'a', b: 'b'}; const b = { c: 'c' } const c = Object.assign(a,b); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
test1
test2

Fastest: N/A

Slowest: N/A

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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 explain what is being tested, compared, and analyzed.

**Benchmark Overview**

The benchmark measures the performance of JavaScript spread operator (`...`) in two different approaches:

1. **Using the Spread Operator with Object Destructuring (test2)**
```javascript
const c = { ...a, ...b };
```
2. **Using `Object.assign()` (test1)**
```javascript
const c = Object.assign(a, b);
```
The benchmark is designed to test the performance of these two approaches on a dataset of 100,000 iterations.

**Comparison of Approaches**

The primary difference between the two approaches is how they handle object merging:

* **Spread Operator (test2)**:
	+ Uses the spread operator (`...`) to create a new object with merged properties.
	+ Preserves the property names and values from both `a` and `b`.
	+ Can be more readable and efficient for simple object merges.
* **`Object.assign()` (test1)**:
	+ Uses the `Object.assign()` method to merge two objects.
	+ Overwrites existing properties with new ones from `b`.

**Pros and Cons of Each Approach**

* **Spread Operator (test2)**:
	+ Pros:
		- More readable and concise code.
		- Can be faster for simple object merges.
	+ Cons:
		- May not work as expected if `a` or `b` are not objects.
		- Can lead to unexpected behavior if properties have different types (e.g., numbers vs. strings).
* **`Object.assign()` (test1)**:
	+ Pros:
		- More predictable and robust behavior, especially when dealing with complex object merges.
		- Works well even if `a` or `b` are not objects.
	+ Cons:
		- Can lead to more verbose code.
		- May be slower than the spread operator for simple object merges.

**Library Usage**

In both test cases, no libraries are used beyond the JavaScript standard library.

**Special JS Features or Syntax**

There are no special JS features or syntax used in this benchmark.

**Other Alternatives**

Alternative approaches to merge objects include:

* Using `Array.prototype.reduce()`:
```javascript
const c = a.reduce((acc, val) => ({ ...acc, [val]: b[val] }), {});
```
* Using a library like Lodash (`_merge()`):
```javascript
const _ = require('lodash');
const c = _.merge(a, b);
```
Keep in mind that these alternatives may have performance implications or added complexity compared to the spread operator and `Object.assign()`.

I hope this explanation helps you understand the benchmark and its objectives!

Related benchmarks:

test spread and assign (version: 0)

Comparing performance of: test1 vs test2

Created: 4 years ago by: Guest

Jump to the latest result

test1

test2

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):