Benchmark: set array index: slice vs lodash set vs Object.assign

HTML Preparation code:


<script src='https://cdn.jsdelivr.net/g/lodash@4(lodash.min.js+lodash.fp.min.js)'></script>

Tests:

slice
var index = 2; var array = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; var output = [ ...array.slice(0, index), 10, ...array.slice(index + 1) ];
Object.assign
var array = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; var output = Object.assign([], array, {2: 10});
lodash set
var array = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]; var output = _.set(2, 10)(array)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
slice
Object.assign
lodash set

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 7 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser/OS: Chrome 135 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
slice	15724734.0 Ops/sec
Object.assign	1201795.6 Ops/sec
lodash set	1401836.1 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data and explain what is being tested in each test case.

The benchmark, named "set array index: slice vs lodash set vs Object.assign", compares three different approaches to set an element at a specific index in an array:

1.  **Slice**: The `Array.prototype.slice()` method returns a shallow copy of a portion of an array.
2.  **Lodash Set**: The Lodash library provides the `_set()` function, which sets the value of a property on an object (or an array) at a specific key (index).
3.  **Object.assign()**: This method is used to add one or more source objects to an existing target object.

**Options Comparison:**

Here's a brief overview of each approach and their pros/cons:

*   **Slice:**
    *   Pros:
        *   Simple, straightforward implementation.
        *   Does not require any additional libraries.
    *   Cons:
        *   Returns a new array, which can be slower for large arrays due to the overhead of creating a new object.
        *   Requires extra memory allocation.

*   **Lodash Set:**
    *   Pros:
        *   Provides a more explicit and controlled way of setting values in an array or object.
        *   Does not require manual looping or indexing.
    *   Cons:
        *   Adds an external dependency on the Lodash library, which can be a performance overhead.
        *   May have additional overhead due to the complexity of the `_set()` function.

*   **Object.assign():**
    *   Pros:
        *   A well-established and widely-supported method for merging objects.
        *   Can also be used to set values in an object or array by using the `null` value as a replacement.
    *   Cons:
        *   Returns the target object, not a new array, which can lead to unexpected behavior if not handled correctly.

**Other Considerations:**

The choice of approach depends on the specific requirements and constraints of your project. For example:

*   If you're working with large datasets or need to perform frequent updates, using `Array.prototype.slice()` might be the most efficient option.
*   If you prefer a more explicit and controlled way of setting values in an array or object, `_set()` from Lodash could be a better choice.

**Library and Special JS Feature:**

The Lodash library is used in one of the test cases. Lodash provides a collection of functional programming helpers that can simplify common tasks. In this case, `_set()` is used to set the value of an element at a specific index in the array.

There are no special JavaScript features or syntax used in these benchmarks. They only use standard JavaScript methods and libraries like Lodash.

**Alternatives:**

Other alternatives for setting values in an array or object could include:

*   Using `Array.prototype.indexOf()` to find the index of the element, then using `Array.prototype.splice()` to replace it.
*   Using a custom implementation with manual looping and indexing.

However, these approaches may be less efficient and more error-prone than the methods used in this benchmark.

Related benchmarks:

set array index: slice vs lodash set vs Object.assign (version: 0)

Comparing performance of: slice vs Object.assign vs lodash set

Created: 5 years ago by: Registered User

Jump to the latest result

slice

Object.assign

lodash set

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):