Benchmark: JavaScript spread operator vs Object.assign performance - TW custom

Tests:

Using the spread operator
const secondObject = { moreData: 'foo bar' } const finalObject = { ...{}, ...secondObject };
Using Object.assign
const secondObject = { moreData: 'foo bar' } const finalObject = Object.assign({}, secondObject);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using the spread operator
Using Object.assign

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down what's being tested in the provided JSON.

The benchmark is comparing the performance of two ways to create a new object by merging an existing object (`secondObject`) into it: using the spread operator (`...`) and `Object.assign()`.

**Option 1: Using the spread operator**

The spread operator (`...`) was introduced in ECMAScript 2018 (ES8) as a shorthand for creating a new object with properties from another object. In this case, the benchmark creates two objects:

* `secondObject` with some data
* `finalObject` created by spreading `secondObject` into an empty object (`{...}`), followed by merging it with another empty object (`{ ... secondObject }`)

The spread operator is generally considered more concise and readable than using `Object.assign()`, but its performance can vary depending on the browser and the specific use case.

**Option 2: Using Object.assign()**

`Object.assign()` is a method that copies properties from one or more source objects into a target object. In this benchmark, it's used to merge `secondObject` into an empty object (`Object.assign({}, secondObject)`). This approach has been around since ECMAScript 2009 (ES5) and is widely supported by browsers.

**Pros and Cons:**

* **Spread Operator:**
	+ Pros:
		- More concise and readable
		- Can be faster, as it avoids the overhead of method calls
	+ Cons:
		- May not be supported in older browsers or environments that don't have ES8 support
		- Can lead to unexpected behavior if not used carefully (e.g., with nested objects)
* **Object.assign():**
	+ Pros:
		- Widely supported by older browsers and environments
		- Less prone to unexpected behavior due to its explicit nature
	+ Cons:
		- More verbose and less readable than the spread operator
		- Can be slower, depending on the browser and implementation

**Library/Feature Used:**

None mentioned in the provided JSON.

No special JavaScript features or syntax are used in this benchmark.

**Alternative Approaches:**

Other ways to merge objects could include using other methods like:

* `Object.create()`: creates a new object with the given prototype
* `Array.prototype.concat()` and then `Object.assign()`: concatenate arrays and convert them to objects using `Object.assign()`
* `reduce()`: use the `reduce()` method to iterate over the properties of one object and merge them into another

Keep in mind that these alternative approaches might have different performance characteristics, readability, or browser support compared to the spread operator and `Object.assign()`.

Let me know if you'd like more information on any of these points!

Related benchmarks:

JavaScript spread operator vs Object.assign performance - TW custom (version: 0)

Comparing performance of: Using the spread operator vs Using Object.assign

Created: 6 years ago by: Guest

Jump to the latest result

Using the spread operator

Using 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):