Benchmark: Object.fromEntries vs reduce v4

Script Preparation code:

var data = ['a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j'];

Tests:

Object.fromEntries
Object.fromEntries(data.map((i) => [i, i]));
Reduce (mutate)
data.reduce((acc, i) => { acc[i] = i; return acc; }, {});
Reduce (spread)
data.reduce((acc, i) => ({ ...acc, [i]: i }), {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.fromEntries
Reduce (mutate)
Reduce (spread)

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark and explain what's being tested.

**Benchmark Purpose**
The purpose of this benchmark is to compare the performance of three different methods for creating an object from an array: `Object.fromEntries`, `reduce` (mutate), and `reduce` (spread).

**Options Compared**

1. **`Object.fromEntries`**: This method creates a new object by iterating over an array of key-value pairs.
2. **`Reduce (mutate)`**: This method uses the `reduce` function to accumulate an object from an array, where each element in the array is used as a key and its corresponding value is added to the accumulator object.
3. **`Reduce (spread)`**: This method uses the `reduce` function with the spread operator (`...`) to create a new object from an array.

**Pros and Cons of Each Approach**

1. **`Object.fromEntries`**:
	* Pros: Simple, readable code; efficient creation of objects.
	* Cons: May have performance overhead due to iteration over the array.
2. **`Reduce (mutate)`**:
	* Pros: Can be more efficient than `Object.fromEntries` since it avoids unnecessary iterations.
	* Cons: Code may look less readable and maintainable, as the accumulator object is modified in place.
3. **`Reduce (spread)`**:
	* Pros: Combines the benefits of both approaches; efficient creation of objects while maintaining readability.
	* Cons: May have performance overhead due to spread operator usage.

**Library and Special JS Features Used**

None of the benchmark methods require any external libraries or special JavaScript features beyond standard ECMAScript 2020 syntax.

**Other Alternatives**
Alternative methods for creating an object from an array could include:

1. `Array.reduce()`: This method creates a new array by reducing it to a single value.
2. Object literals: Directly creating an object with key-value pairs using curly braces (`{}`).
3. Array.map(): This method returns a new array where each element is transformed according to a provided function.

Keep in mind that these alternative methods might have different performance characteristics and trade-offs compared to the benchmarked approaches.

Related benchmarks:

Object.fromEntries vs reduce v4 (version: 0)

Comparing performance of: Object.fromEntries vs Reduce (mutate) vs Reduce (spread)

Created: 3 years ago by: Guest

Jump to the latest result

Object.fromEntries

Reduce (mutate)

Reduce (spread)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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