Benchmark: _.omit vs delete of map

HTML Preparation code:

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

Script Preparation code:

data = { a:'koko',b:'koko',c:'koko',d:'koko',e:'koko',f:'koko',g:'koko',h:'koko',i:'koko',x:'asd' }

Tests:

Delete of map
['a','x'].map(key => delete data.key) return data
Omit
return _.omit(data, ['a','x'])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Delete of map
Omit

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year 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
Delete of map	24716110.0 Ops/sec
Omit	1559007.9 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**Overview**

The benchmark measures the performance difference between using `delete` to remove properties from an object (`_.omit`) and using `Object.keys().filter()` (along with Lodash's `omit` function) in JavaScript.

**Options being compared**

Two approaches are being compared:

1. **Direct deletion**: Using `delete data.key` to remove properties from the `data` object.
2. **Lodash's omit**: Using Lodash's `_omit` function to filter out specific keys from the `data` object.

**Pros and Cons of each approach:**

**Direct Deletion (Delete)**

Pros:

* Typically faster, as it avoids the overhead of function calls and array operations.
* Often considered more "native" or efficient way to remove properties from an object.

Cons:

* May not work correctly if the property names are strings that contain special characters or non-ASCII values.
* Can lead to unexpected behavior if used with nested objects (i.e., `data.a` would delete `a` from both the top-level and any nested objects).

**Lodash's Omit**

Pros:

* More predictable and robust, as it handles string property names correctly and ignores properties that don't match the filter.
* Often considered more readable and maintainable, especially for complex filtering scenarios.

Cons:

* May be slower due to the overhead of function calls and array operations.
* Relies on Lodash's implementation, which may have internal optimizations or quirks not apparent from the surface.

**Library usage**

Lodash is a popular JavaScript utility library that provides a wide range of functions for tasks like string manipulation, array processing, and more. In this benchmark, Lodash's `_omit` function is used to filter out specific keys from the `data` object.

**Special JS feature/syntax**

None mentioned in this explanation. However, it's worth noting that some JavaScript features or syntax might affect the performance of these approaches (e.g., using `let` or `const` instead of `var` for variable declarations). But in this case, no specific features are being leveraged.

**Other alternatives**

For those looking to optimize object removal in JavaScript, consider:

* Using a library like Lodash's own `omit` function, as it provides a more predictable and robust way to filter objects.
* Implementing your own custom filtering functions using techniques like `Object.keys()` or `for...in`.
* Using modern JavaScript features like `Map` or `Set` to represent the object's properties (if available in older browsers).

Keep in mind that performance optimizations should always be evaluated on a per-project basis, considering factors like data size, complexity, and specific use cases.

Related benchmarks:

_.omit vs delete of map (version: 0)

Perf lodash.omit vs Object.keys().filter

Comparing performance of: Delete of map vs Omit

Created: 5 years ago by: Guest

Jump to the latest result

Delete of map

Omit

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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