Benchmark: Object.fromEntries vs reduce vs classic for v3

Script Preparation code:

const data = Array.from(Array(10000).keys());

Tests:

Object.fromEntries
Object.fromEntries(data.map((idx) => [`id-${idx}`, idx]));
Reduce (reuse object)
data.reduce((acc, idx) => { acc[`id-${idx}`] = idx; return acc; }, {});
For
const a = {} for (let idx of data) { a[`id-${idx}`] = idx; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.fromEntries
Reduce (reuse object)
For

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 22 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/147.0.0.0 Safari/537.36 Edg/147.0.0.0

Browser/OS: Chrome 147 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Object.fromEntries	749.9 Ops/sec
Reduce (reuse object)	1162.1 Ops/sec
For	1273.5 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark you provided compares three different methods for creating an object from an array of integers ranging from 0 to 9999. The methods being compared are:

1. **Using `Object.fromEntries`**: This method leverages the `Object.fromEntries()` function, which takes an iterable of key-value pairs (in this case, generated using `data.map()`) and converts it into an object.

2. **Using `reduce`**: This method utilizes the `reduce()` array method to iterate over the `data` array. It accumulates the key-value pairs into an object, effectively building it up as it iterates.

3. **Using a classic `for` loop**: This method employs a traditional `for` loop to iterate over the `data` array and directly assigns key-value pairs to an object.

### Performance Results

From the benchmark results:

- **For Loop**: 736.25 executions per second
- **Reduce (Reuse Object)**: 711.06 executions per second
- **Object.fromEntries**: 524.42 executions per second

### Pros and Cons of Each Approach

1. **Object.fromEntries**:
   - **Pros**:
     - Concise and clear syntax.
     - Directly expresses the intent of converting pairs into an object.
   - **Cons**:
     - Performance is slower compared to other methods.
     - Can be less familiar to those who are not accustomed to functional programming styles in JavaScript.

2. **Reduce**:
   - **Pros**:
     - More functional in style, which may appeal to developers with a background in functional programming.
     - Avoids the need for a separate variable for accumulation (as the accumulator is passed into the function).
   - **Cons**:
     - Slightly harder to read and understand, especially for those unfamiliar with `reduce`.
     - Potential for reduced performance compared to simple loops, especially with large datasets.

3. **For Loop**:
   - **Pros**:
     - Traditional and easily understood by all developers.
     - Tends to have better performance in JavaScript engines, as it minimizes the abstraction overhead.
   - **Cons**:
     - More verbose and less modern in appearance; can lead to more boilerplate code.
     - Less declarative than the other methods, which can lead to a misunderstanding if not documented well.

### Other Considerations

- **Readability**: For future maintainers of the code, readability is crucial. While concise methods like `Object.fromEntries` and `reduce` offer clarity in intent, they can sometimes obfuscate performance implications.
- **Browser Differences**: The performance of these methods can vary across different JavaScript engines; thus, benchmarking in the target environment is essential.
- **Array Size**: The benchmark runs with 10,000 items; performance may differ with smaller or larger datasets.

### Alternatives

- **Using `Map`**: Instead of using plain objects, one could utilize a `Map` for key-value storage, which allows for a collection of key-value pairs where keys can be of any type. The `Map` can be converted to an object afterward if needed.
  
- **Object.entries with forEach**: Another approach could involve using `Object.entries` along with `forEach`, although this also has potential performance drawbacks due to the overhead of extra method calls.

### Special Features/JS Syntax

There are no specific advanced JavaScript syntaxes or features being tested in this benchmark; all methods used are standard JavaScript capabilities available in ES6 and later. The `map()` and `reduce()` methods are part of the Array prototype and are widely used for functional programming within JavaScript.

Related benchmarks:

Object.fromEntries vs reduce vs classic for v3 (version: 1)

Comparing performance of: Object.fromEntries vs Reduce (reuse object) vs For

Created: one year ago by: Guest

Jump to the latest result

Object.fromEntries

Reduce (reuse object)

For

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):