Benchmark: reduce with object spread vs foreach with adding

Tests:

Using reduce and the spread operator
const styles = { foo: { color: 'red', }, bar: { color: 'green', '&:focus': { color: 'blue', }, }, foo2: { color: 'red', }, bar2: { color: 'green', '&:focus': { color: 'blue', }, }, foo3: { color: 'red', }, bar3: { color: 'green', '&:focus': { color: 'blue', }, }, foo4: { color: 'red', }, bar4: { color: 'green', '&:focus': { color: 'blue', }, }, }; Object .keys(styles) .reduce((classes, selector) => ({ ...classes, [selector]: selector, }), {});
Using map and adding to an object
const styles = { foo: { color: 'red', }, bar: { color: 'green', '&:focus': { color: 'blue', }, }, foo2: { color: 'red', }, bar2: { color: 'green', '&:focus': { color: 'blue', }, }, foo3: { color: 'red', }, bar3: { color: 'green', '&:focus': { color: 'blue', }, }, foo4: { color: 'red', }, bar4: { color: 'green', '&:focus': { color: 'blue', }, }, }; const obj = {}; Object .keys(styles) .forEach(style => { obj[style] = style; })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Using reduce and the spread operator
Using map and adding to an object

Fastest: N/A

Slowest: N/A

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

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Let's dive into the world of JavaScript microbenchmarks!

The provided benchmark tests two approaches to achieve similar results: using `reduce` with object spread (`Object.keys(styles).reduce(...)`) and using `forEach` with adding to an object (`Object.keys(styles).forEach(style => { ... })`). The test case uses a nested object structure, where the keys are styles and the values are objects with additional properties.

**Options being compared:**

1. **Reduce**: This method iterates over the array of keys returned by `Object.keys()`, reducing it to an object with the desired key-value pairs.
2. **ForEach**: This method iterates over the array of keys returned by `Object.keys()`, executing a callback function for each key.

**Pros and Cons:**

1. **Reduce**:
	* Pros:
		+ More concise and expressive code.
		+ Can be more efficient in terms of memory usage, as it creates an object with fewer properties.
	* Cons:
		+ May have performance issues if the input array is very large or if the callback function is computationally expensive.
2. **ForEach**:
	* Pros:
		+ Can be easier to understand and debug, especially for complex logic.
		+ Does not create an object with fewer properties, which can be beneficial in certain scenarios.
	* Cons:
		+ More verbose code compared to `reduce`.
		+ May incur a performance penalty due to the need to create and modify an object.

**Library and its purpose:**

The `Object.keys()` method is a built-in JavaScript library that returns an array of strings representing the keys of an object. The `forEach()` method is also a built-in JavaScript library that iterates over an array or iterable object, executing a callback function for each item.

**Special JS feature or syntax:**

None mentioned in this benchmark.

**Other considerations:**

* The benchmark measures the performance difference between two approaches, which is useful for identifying optimization opportunities.
* The use of `Object.keys()` and `forEach()` eliminates any potential differences in performance due to the order of operations or memory allocation.

**Alternatives:**

1. **Loops**: Using traditional loops (e.g., `for` loops) instead of array methods like `reduce` and `forEach`.
2. **Map**: Using the `Map` object instead of objects with dynamic keys.
3. **Array methods**: Exploring other array methods, such as `filter()`, `map()`, or `every()`, for comparison.

In conclusion, this benchmark helps developers understand the performance implications of using different approaches to achieve similar results in JavaScript. By comparing `reduce` and `forEach`, we can identify which approach is more efficient and suitable for specific use cases.

Related benchmarks:

reduce with object spread vs foreach with adding (version: 0)

Comparing performance of: Using reduce and the spread operator vs Using map and adding to an object

Created: 7 years ago by: Guest

Jump to the latest result

Using reduce and the spread operator

Using map and adding to an object

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):