Benchmark: Object.assign vs key assign

Script Preparation code:

var input = { foo: 'lorem', bar: null }

Tests:

Key assign
const { foo, bar } = input; const result = {}; if (foo) { result['foo'] = foo; } if (bar) { result['bar'] = bar; }
Object.assign
const { foo, bar } = input; const result = {}; Object.assign( foo ? { foo } : {}, bar ? { bar } : {} );

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Key assign
Object.assign

Fastest: N/A

Slowest: N/A

Latest run results:

No previous 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 benchmark and its test cases.

**Benchmark Overview**

The benchmark compares two approaches for assigning properties to an object: using key assignment (`const { foo, bar } = input; const result = {}; if (foo) { result['foo'] = foo; } if (bar) { result['bar'] = bar; };`) and using `Object.assign()`.

**Options Compared**

The two options are:

1. **Key Assignment**: Using destructuring assignment to extract properties from the `input` object and then assigning them to a new object (`result`). This approach uses explicit property assignments.
2. **Object.assign()**: Passing an initial object with only the assigned properties (either `{ foo }` or `{ bar }`) to `Object.assign()` to merge it with an empty object.

**Pros and Cons**

1. **Key Assignment**
	* Pros: Simple, readable, and maintainable code. No overhead of function calls or additional objects.
	* Cons: May be slower due to the need to check if properties exist (`foo` and `bar`) before assigning them.
2. **Object.assign()**
	* Pros: Faster execution, as it avoids the overhead of explicit property assignments and checks for existence. Also, it can handle nested properties more efficiently.
	* Cons: Less readable code, especially when dealing with complex object structures or multiple assignees.

**Library**

There is no external library mentioned in the benchmark definition. However, `Object.assign()` is a built-in JavaScript method that comes with the language.

**Special JS Feature/Syntax**

None of the provided test cases use any special JavaScript features or syntax beyond what's considered standard (ECMAScript 2020).

**Other Alternatives**

For this specific benchmark, the alternative approaches would be:

1. Using `Object.assign()` in a different way:
```javascript
const { foo, bar } = input;
const result = {};
result.foo = foo;
result.bar = bar;
```
2. Implementing a custom assignment function to avoid using `Object.assign()`.
3. Using a library like Lodash that provides an `assign` method for object merging.

In summary, the benchmark is testing two approaches for assigning properties to an object: key assignment and `Object.assign()`. The choice between these options depends on readability, performance, and code complexity.

Related benchmarks:

Object.assign vs key assign (version: 0)

Comparing performance of: Key assign vs Object.assign

Created: 5 years ago by: Guest

Jump to the latest result

Key assign

Object.assign

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):