Benchmark: remove undefined from object. entries.filter vs for of vs for in

Script Preparation code:

const testObject = {
    a: 'a',
    b: undefined,
    c: 'c',
    d: undefined,
    e: undefined
}

Tests:

filter object entries
const testObject = { a: 'a', b: undefined, c: 'c', d: undefined, e: undefined } Object.fromEntries(Object.entries(testObject).filter(([_, value]) => value !== undefined))
for of Object.entries
const testObject = { a: 'a', b: undefined, c: 'c', d: undefined, e: undefined } const testObjectCopy = {...testObject} for (const [prop, value] of Object.entries(testObjectCopy)) if (value === undefined) delete testObjectCopy[prop]
for in
const testObject = { a: 'a', b: undefined, c: 'c', d: undefined, e: undefined } const testObjectCopy = {...testObject} for (const prop in testObjectCopy) if (testObjectCopy.hasOwnProperty(prop) && testObjectCopy[prop] === undefined) delete testObjectCopy[prop]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
filter object entries
for of Object.entries
for in

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 JSON and benchmark results in an easy-to-understand format.

**Benchmark Overview**

The provided benchmark measures the performance of three different approaches to remove `undefined` values from an object: using `filter()`, `for...of`, and `for...in`. The benchmark aims to determine which approach is the most efficient.

**Approaches Compared**

1. **Filter()**: This approach uses the `Array.prototype.filter()` method to create a new array with only the elements that pass the test implemented by the provided function.
2. **For...of (Object.entries)**: This approach iterates over an array of key-value pairs using a `for...of` loop, filtering out the values that are equal to `undefined`.
3. **For...in**: This approach uses a traditional `for...in` loop to iterate over the object's properties, checking if each value is `undefined` and deleting it if so.

**Pros and Cons of Each Approach**

1. **Filter()**:
	* Pros: Efficient and concise, as it creates a new array with filtered values.
	* Cons: Creates an extra memory allocation for the new array, which can be costly in terms of performance.
2. **For...of (Object.entries)**:
	* Pros: More modern and efficient than traditional `for...in`, as it avoids the overhead of `hasOwnProperty()` checks.
	* Cons: May require more memory to store the internal iterator object.
3. **For...in**:
	* Pros: Simple and easy to implement, but may be slower due to the overhead of property checking and deleting.
	* Cons: Less modern and less efficient than the other two approaches.

**Library and Special JS Features**

The benchmark uses none of its own libraries or special JavaScript features. It relies solely on built-in methods and syntax for each approach.

**Other Alternatives**

Some alternative approaches to remove `undefined` values from an object could include:

* Using a library like Lodash or Ramda, which provide utility functions for filtering and manipulating objects.
* Using a map function with a predicate callback
* Using the spread operator (`{...}`) to create a new object with filtered properties

Keep in mind that these alternatives may introduce additional dependencies or overhead compared to using built-in methods.

**Benchmark Results**

The latest benchmark results show that:

1. **For...in** is currently the fastest approach, with an average of 1483802 executions per second.
2. **Filter()** is the next fastest, with an average of 1550265 executions per second.
3. **For...of (Object.entries)** is the slowest, with an average of 1721107 executions per second.

These results may vary depending on the specific use case and environment in which the benchmark is run.

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
filter object entries	1483802.0 Ops/sec
for of Object.entries	1550265.8 Ops/sec
for in	1721107.8 Ops/sec

Related benchmarks:

remove undefined from object. entries.filter vs for of vs for in (version: 0)

Comparing performance of: filter object entries vs for of Object.entries vs for in

Created: 6 months ago by: Guest

Jump to the latest result

filter object entries

for of Object.entries

for in

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):