Benchmark: Object spread vs assign of another object

Tests:

spread two objects
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 10).reduce((acc, num) => { return { ...acc, ...{ [num]: num } } }, {})
assign two objects
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 10).reduce((acc, num) => { return Object.assign(acc, { [num]: num }) }, {})
assign from empty object
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 10).reduce((acc, num) => { return Object.assign({}, acc, { [num]: num }) }, {})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
spread two objects
assign two objects
assign from empty object

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's being tested, along with the pros and cons of each approach.

**Benchmark Definition**
The benchmark is comparing three approaches for merging two objects in JavaScript:

1. `Object.assign()`
2. Object spread operator (`...`)
3. Merging from an empty object (`Object.assign({}, ...)`

**Options Compared**

* **`Object.assign()`**: This method takes multiple source objects and merges them into a target object. It's been a part of the JavaScript standard library since ECMAScript 2015 (ES6).
* **Object Spread Operator (`...`)**: Introduced in ES6, this operator allows you to spread the properties of an object onto another object.
* **Merging from an empty object (`Object.assign({}, ...)`)**: This approach uses `Object.assign()` with two arguments: an initial value (an empty object) and a source object. The result is merged back into the initial value.

**Pros and Cons**

* **`Object.assign()`**:
	+ Pros: Simple, widely supported, and reliable.
	+ Cons: Can be slow due to its method invocation overhead, and it only works with objects.
* **Object Spread Operator (`...`)**:
	+ Pros: Convenient, expressive, and often faster than `Object.assign()`.
	+ Cons: Requires modern browsers or Node.js versions that support ES6+ syntax.
* **Merging from an empty object (`Object.assign({}, ...)`)**:
	+ Pros: Similar performance to using `Object.assign()` directly, but with the added benefit of creating a new object if the initial value is an object (i.e., not null or undefined).
	+ Cons: May be less intuitive than using `Object.assign()` directly.

**Library and Special Features**

None mentioned in the provided benchmark definition. However, it's worth noting that some libraries, like Lodash, provide additional methods for merging objects, such as `_.merge()`, which might be used in other benchmarks.

**Other Considerations**

When choosing between these approaches, consider the following:

* If you need to merge two objects with similar properties, but want a simple and reliable solution, use `Object.assign()`.
* For more concise and expressive code, use the Object Spread Operator (`...`).
* When merging from an empty object is necessary (e.g., to avoid overwriting existing properties), consider using `Object.assign({}, ...)`.

Related benchmarks:

Object spread vs assign of another object (version: 0)

Comparing performance of: spread two objects vs assign two objects vs assign from empty object

Created: 4 years ago by: Guest

Jump to the latest result

spread two objects

assign two objects

assign from empty object

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):