Benchmark: JavaScript spread operator vs Object.assign performance with empty object

Tests:

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

Latest run results:

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

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Let's dive into the JavaScript benchmark on MeasureThat.net.

**Benchmark Definition**

The provided JSON represents a benchmark that tests the performance of two approaches to merge objects in JavaScript: using the spread operator (`...`) and `Object.assign()`. The benchmark is designed to compare these two methods when merging an empty object with another object containing some data.

**Options Compared**

Two options are compared:

1. **Using the Spread Operator**: This method uses the spread operator (`...`) to merge the objects. It creates a new object by spreading the properties of `firstObject` and then spreads `secondObject` into that new object.
2. **Using Object.assign()**: This method uses the `Object.assign()` function to merge the objects. It passes an empty object as the first argument, followed by `firstObject` and then `secondObject`.

**Pros and Cons**

Both approaches have their trade-offs:

* Using the Spread Operator:
	+ Pros: Concise syntax, easy to read, and understand.
	+ Cons: Can be slower due to function call overhead.
* Using Object.assign():
	+ Pros: Faster than spread operator for large objects, as it avoids function call overhead.
	+ Cons: Less concise syntax, can be less readable.

**Library and Purpose**

No external libraries are used in this benchmark. The `Object` object is a built-in JavaScript object that provides various methods, including `assign()`, to manipulate objects.

**Special JS Feature or Syntax**

The spread operator (`...`) is a relatively new feature introduced in ECMAScript 2018 (ES9). It allows you to expand an array into a set of key-value pairs within an object literal. The syntax is used extensively in modern JavaScript code and provides a concise way to merge objects.

**Other Alternatives**

Other ways to merge objects in JavaScript include:

* Using the `for...in` loop to iterate over the properties of one object and add them to another.
* Using a library like Lodash, which provides various utility functions, including `merge()` for merging objects.
* Using a function that takes two objects as arguments and returns a new object with merged properties.

However, these alternatives are generally less efficient or more verbose than using the spread operator or `Object.assign()`.

Related benchmarks:

JavaScript spread operator vs Object.assign performance with empty object (version: 0)

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

Created: 5 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):