Benchmark: lodash mapValues vs vanilla Object.keys foreach vs lodash reduce

HTML Preparation code:

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

Script Preparation code:

var obj = {}
for (let i = 0; i < 1000; ++i) {
    obj[`a${i}`] = i;
}
var transform = (n) => n * n + 1;

Tests:

lodash mapValues
const newObj = _.mapValues(obj, (v, k) => transform(v));
vanilla object.keys
const newObj = {}; Object.keys(obj).forEach((key) => { newObj[key] = transform(obj[key]); });
lodash reduce
const newObj = _.reduce(obj, (acc, val, key) => { acc[key] = transform(val); return acc; })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
lodash mapValues
vanilla object.keys
lodash reduce

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared, and the pros and cons of each approach.

**Benchmark Overview**

The benchmark is designed to compare three approaches for transforming data in JavaScript:

1. `lodash mapValues`
2. Vanilla `Object.keys` with a `forEach` loop
3. `lodash reduce`

**Options Compared**

The benchmark compares the performance of these three approaches on a dataset that consists of 1000 objects, each with an "a" key containing a unique integer value.

**Approach 1: Lodash `mapValues`**

* Purpose: To create a new object by mapping over the original object's keys and values.
* Implementation: The benchmark uses the `_mapValues` function from Lodash, which takes two arguments: the source object (`obj`) and a transform function (`transform`). It returns a new object with transformed values.

Pros:

* Concise and readable implementation
* Optimized for performance by leveraging Lodash's optimized caching mechanism

Cons:

* Adds an external dependency (Lodash) that may not be present in all environments
* May have slower startup times due to the need to load Lodash

**Approach 2: Vanilla `Object.keys` with a `forEach` loop**

* Purpose: To create a new object by iterating over the keys of the original object and assigning transformed values.

Pros:

* No external dependencies required
* Fast startup times since no additional libraries are loaded

Cons:

* More verbose implementation compared to `mapValues`
* Less efficient than `mapValues` due to the need for an explicit loop

**Approach 3: Lodash `reduce`**

* Purpose: To create a new object by reducing the original object's values using a transform function.

Pros:

* Similar to `mapValues`, but with additional flexibility in terms of accumulator and callback functions
* Still optimized for performance due to Lodash's caching mechanism

Cons:

* May have slower performance compared to `mapValues` due to the additional complexity of the reducer function

**Library: Lodash**

Lodash is a popular JavaScript utility library that provides a collection of high-quality, consistently-tested functions for various tasks. In this benchmark, `_mapValues` and `_reduce` are used to transform data efficiently.

**Special JS Feature/Syntax**

There doesn't appear to be any special JavaScript features or syntax being tested in this benchmark. However, if there were, it would likely involve something like ES6 arrow functions (`=>`) or template literals (`\${}`), which are not relevant to the implementation details of these three approaches.

**Other Alternatives**

If you wanted to implement an alternative approach to transforming data, some possible options might include:

* Using `Array.prototype.map()` and `Object.fromEntries()`
* Utilizing a custom iterative approach with loops and caching
* Leveraging a third-party library like Immutable.js

Keep in mind that each of these alternatives would have their own trade-offs in terms of performance, readability, and maintainability.

Latest run results:

Run details: (Test run date: 8 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:132.0) Gecko/20100101 Firefox/132.0

Browser/OS: Firefox 132 on Windows

View result in a separate tab

Test name	Executions per second
lodash mapValues	4950.8 Ops/sec
vanilla object.keys	6280.2 Ops/sec
lodash reduce	4790.5 Ops/sec

Related benchmarks:

lodash mapValues vs vanilla Object.keys foreach vs lodash reduce (version: 2)

Comparing performance of: lodash mapValues vs vanilla object.keys vs lodash reduce

Created: 2 years ago by: Registered User

Jump to the latest result

lodash mapValues

vanilla object.keys

lodash reduce

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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