Benchmark: Reduce and Spread vs. Foreach and Mutate

Script Preparation code:

var objectsArray = Array(1000).fill(() => {
  const key = Math.random().toString(36).substring(2, 5);
  const value = Math.random().toString(36).substring(2, 5);
  return {[key]: value};
});

AخA
 
var objectsArray = Array(1000).fill(() => {  const key = Math.random().toString(36).substring(2, 5);  const value = Math.random().toString(36).substring(2, 5);  return {[key]: value};});

Tests:

Reduce and Spread
var combined = objectsArray.reduce((memo, obj) => ({...memo, ...obj}), {});
var combined = objectsArray.reduce((memo, obj) => ({...memo, ...obj}), {});
ForEach and Mutate (for .. in loop)
var combined = {} objectsArray.forEach(obj => { for (key in obj) { combined[key] = obj[key]; } });
var combined = {}
objectsArray.forEach(obj => {
for (key in obj) {
combined[key] = obj[key];
}
});
Mutate with Object.assign
var combined = Object.assign(...objectsArray)
var combined = Object.assign(...objectsArray)
Foreach and Mutate (Object.assign)
var combined = {} objectsArray.forEach(obj => Object.assign(combined, obj));
var combined = {}
objectsArray.forEach(obj => Object.assign(combined, obj));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
Reduce and Spread
ForEach and Mutate (for .. in loop)
Mutate with Object.assign
Foreach and Mutate (Object.assign)

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:130.0) Gecko/20100101 Firefox/130.0

Browser/OS: Firefox 130 on Linux

View result in a separate tab

Test name	Executions per second
Reduce and Spread	5187.0 Ops/sec
ForEach and Mutate (for .. in loop)	1095.9 Ops/sec
Mutate with Object.assign	11274.5 Ops/sec
Foreach and Mutate (Object.assign)	8905.8 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 4 months ago):

Benchmark Overview

The provided benchmark, "Reduce and Spread vs. Foreach and Mutate", compares the performance of four different approaches to merge an array of objects into a single object.

Approaches Compared

Reduce and Spread: This approach uses the reduce() method with the spread operator (...) to merge the objects.
ForEach and Mutate (for .. in loop): This approach uses a traditional for loop to iterate over the array of objects and assign each property to the resulting object using the dot notation (obj[key] = combined[key]).
Mutate with Object.assign: This approach uses the Object.assign() method to merge the objects.
Foreach and Mutate (Object.assign): Similar to the previous one, but uses Object.assign() inside a forEach loop.

Pros and Cons of Each Approach

Reduce and Spread:
- Pros: Efficient, concise, and modern syntax.
- Cons: May not be supported in older browsers or versions of JavaScript that don't have this method (e.g., Internet Explorer 11).
ForEach and Mutate (for .. in loop):
- Pros: Widely supported across different browsers and versions of JavaScript.
- Cons: Can be verbose, error-prone, and less readable than other approaches.
Mutate with Object.assign:
- Pros: Familiar syntax for developers who have worked with Object.assign() before.
- Cons: May not be the most efficient way to merge objects, as it creates a new object each time.
Foreach and Mutate (Object.assign):
- Pros: Similar to the previous one, but avoids the potential issue of creating too many intermediate objects.
- Cons: Still may not be the most efficient approach.

Library Used

In this benchmark, Array.prototype.reduce() is used as a built-in JavaScript method. No external libraries are required.

Special JS Feature or Syntax

The Object.assign() method and the spread operator (...) are features introduced in ECMAScript 2015 (ES6). While not strictly necessary for older browsers, they can provide a more concise and modern way of performing certain tasks.

Other Alternatives

If you want to explore other approaches, you might consider:

Using concat() instead of spread operator (...).
Using slice() to create a shallow copy of the array before merging.
Using a third-party library like Lodash or Underscore.js for utility functions like merge() or reduce().
Using a different data structure, such as an object with nested properties, instead of an array of objects.

Keep in mind that each approach has its trade-offs and may be better suited for specific use cases.

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark, "Reduce and Spread vs. Foreach and Mutate", compares the performance of four different approaches to merge an array of objects into a single object.

**Approaches Compared**

1. **Reduce and Spread**: This approach uses the `reduce()` method with the spread operator (`...`) to merge the objects.
2. **ForEach and Mutate (for .. in loop)**: This approach uses a traditional `for` loop to iterate over the array of objects and assign each property to the resulting object using the dot notation (`obj[key] = combined[key]`).
3. **Mutate with Object.assign**: This approach uses the `Object.assign()` method to merge the objects.
4. **Foreach and Mutate (Object.assign)**: Similar to the previous one, but uses `Object.assign()` inside a `forEach` loop.

**Pros and Cons of Each Approach**

1. **Reduce and Spread**:
	* Pros: Efficient, concise, and modern syntax.
	* Cons: May not be supported in older browsers or versions of JavaScript that don't have this method (e.g., Internet Explorer 11).
2. **ForEach and Mutate (for .. in loop)**:
	* Pros: Widely supported across different browsers and versions of JavaScript.
	* Cons: Can be verbose, error-prone, and less readable than other approaches.
3. **Mutate with Object.assign**:
	* Pros: Familiar syntax for developers who have worked with `Object.assign()` before.
	* Cons: May not be the most efficient way to merge objects, as it creates a new object each time.
4. **Foreach and Mutate (Object.assign)**:
	* Pros: Similar to the previous one, but avoids the potential issue of creating too many intermediate objects.
	* Cons: Still may not be the most efficient approach.

**Library Used**

In this benchmark, `Array.prototype.reduce()` is used as a built-in JavaScript method. No external libraries are required.

**Special JS Feature or Syntax**

The `Object.assign()` method and the spread operator (`...`) are features introduced in ECMAScript 2015 (ES6). While not strictly necessary for older browsers, they can provide a more concise and modern way of performing certain tasks.

**Other Alternatives**

If you want to explore other approaches, you might consider:

* Using `concat()` instead of spread operator (`...`).
* Using `slice()` to create a shallow copy of the array before merging.
* Using a third-party library like Lodash or Underscore.js for utility functions like `merge()` or `reduce()`.
* Using a different data structure, such as an object with nested properties, instead of an array of objects.

Keep in mind that each approach has its trade-offs and may be better suited for specific use cases.

Related benchmarks:

Reduce and Spread vs. Foreach and Mutate (version: 0)

Comparing performance of: Reduce and Spread vs ForEach and Mutate (for .. in loop) vs Mutate with Object.assign vs Foreach and Mutate (Object.assign)

Created: 4 years ago by: Guest

Jump to the latest result

Reduce and Spread

ForEach and Mutate (for .. in loop)

Mutate with Object.assign

Foreach and Mutate (Object.assign)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 4 months ago):