Benchmark: lodash assign vs spread

HTML Preparation code:

<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Tests:

lodash
const oldObject = {test: true}; const newobj = _.assign({}, oldObject, {test: false});
spread
const oldObject = {test: true}; const newobj = {...oldObject, test: false};

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash
spread

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 benchmark and its test cases.

**Benchmark Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided JSON represents a benchmark named "lodash assign vs spread". This benchmark compares two approaches for assigning properties to an object: using the Lodash library's `assign()` function versus using the spread operator (`...`).

**Script Preparation Code**

The HTML preparation code includes a script tag that loads the Lodash JavaScript library version 4.17.5.

```html
<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>
```

This suggests that the benchmark is designed to test the performance of `assign()` versus the spread operator in a controlled environment, isolating Lodash's library overhead from other factors.

**Test Cases**

There are two individual test cases:

1. **Lodash Assign**: The first test case uses Lodash's `assign()` function to create a new object by assigning properties from an existing object (`oldObject`) and another object (`{test: false}`). The benchmark definition code is:
```javascript
const oldObject = {test: true};
const newobj = _.assign({}, oldObject, {test: false});
```

This test case likely measures the performance of Lodash's `assign()` function in creating a new object with assigned properties.

2. **Spread Operator**: The second test case uses the spread operator (`...`) to create a new object by spreading an existing object (`oldObject`) and assigning a property from another object (`{test: false}`). The benchmark definition code is:
```javascript
const oldObject = {test: true};
const newobj = {...oldObject, test: false};
```

This test case likely measures the performance of the spread operator in creating a new object with assigned properties.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Lodash Assign**:
	+ Pros: Lodash's `assign()` function is designed for this specific use case, and it may be more efficient due to its optimized implementation.
	+ Cons: Lodash adds an external library dependency, which can affect overall benchmark performance.
* **Spread Operator**:
	+ Pros: The spread operator is a built-in JavaScript feature that does not require any additional libraries or dependencies.
	+ Cons: The spread operator may be slower than Lodash's `assign()` function due to its dynamic syntax and potential overhead.

**Library and Syntax**

In the first test case, Lodash is used as a library. Its purpose is to provide a convenient way to perform operations on objects that would otherwise require manual property assignment or other workarounds.

The second test case uses the spread operator, which is a built-in JavaScript feature. The syntax `...` is called "rest parameters" and allows for creating new objects by spreading existing objects.

**Special JS Feature**

This benchmark does not use any special JavaScript features beyond the spread operator, as it is already part of the language. However, it's worth noting that Lodash itself uses some internal optimizations and helper functions to improve its performance.

**Alternatives**

Other alternatives for assigning properties to an object in JavaScript include:

* Using `Object.assign()` (a built-in method)
* Manual property assignment using dot notation or bracket notation
* Using a library like Ramda's `assoc` function

However, the benchmark is specifically comparing two approaches: Lodash's `assign()` function and the spread operator.

Related benchmarks:

lodash assign vs spread (version: 0)

Comparing performance of: lodash vs spread

Created: 5 years ago by: Guest

Jump to the latest result

lodash

spread

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):