Benchmark: spread vs mutation vs Object.assign for reduce callback vs for...of loop vs for loop 30K iterations

Tests:

with spread operator
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 30000).reduce((acc, num) => { return { ...acc, [num]: num } }, {})
with mutation
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 30000).reduce((acc, num) => { acc[num] = num return acc }, {})
with object assign
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } range(0, 30000).reduce((acc, num) => { return Object.assign(acc, {[num]: num}) }, {})
with for...of loop
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } const items = range(0, 30000); let result = {}; for(let item of items) { result[item] = item; }
with for loop
const range = (from, to) => { const output = [] for(var x = from; x < to; x++){ output.push(x) } return output } const items = range(0, 30000); let result = {}; for(let i = 0; i < items.length; i += 1) { result[items[i]] = items[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
with spread operator
with mutation
with object assign
with for...of loop
with for loop

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Windows

View result in a separate tab

Test name	Executions per second
with spread operator	0.7 Ops/sec
with mutation	741.3 Ops/sec
with object assign	25.5 Ops/sec
with for...of loop	1132.7 Ops/sec
with for loop	1206.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**Benchmark Overview**

The benchmark measures the performance of four different approaches to populate an object with values from a range:

1. Using a `for` loop
2. Using a `for...of` loop
3. Using mutation (directly assigning values to the object)
4. Using the spread operator (`Object.assign`)

**Approach 1: For Loop**

This approach uses a traditional `for` loop to iterate over the range and assign each value to the object.

Pros:

* Easy to understand and implement
* Works well for small to medium-sized ranges

Cons:

* Can be slow for large ranges due to the overhead of the loop control and array indexing

**Approach 2: For...Of Loop**

This approach uses a `for...of` loop, which is more concise and efficient than a traditional `for` loop. It also allows for easier iteration over arrays.

Pros:

* More concise and readable code
* Can be faster for large ranges due to the optimized loop control

Cons:

* May not work well with older browsers or versions of JavaScript that don't support `for...of`

**Approach 3: Mutation**

This approach uses direct assignment to add values to the object.

Pros:

* Very concise and easy to understand
* Works well for small to medium-sized ranges

Cons:

* Can be slow due to the overhead of the assignment operation
* May lead to unexpected behavior if not used carefully

**Approach 4: Spread Operator**

This approach uses the spread operator (`Object.assign`) to create a new object and assign values from an array.

Pros:

* Very concise and easy to understand
* Can be faster than mutation for large ranges due to optimized assignment operations

Cons:

* May not work well with older browsers or versions of JavaScript that don't support `Object.assign`
* May lead to unexpected behavior if not used carefully (e.g., if the object is modified while being assigned to)

**Other Considerations**

* The use of a spread operator (`Object.assign`) allows for efficient assignment of values from an array, but it requires careful consideration of the implications of modifying an existing object.
* The `for...of` loop provides a more concise and readable alternative to traditional `for` loops, but its performance may vary depending on the browser and JavaScript version.

**Alternative Approaches**

Some other approaches that could be considered for this benchmark include:

* Using a library like Lodash or Ramda, which provide optimized functions for working with arrays and objects.
* Using a more modern approach like Array.prototype.reduce() or Object.fromEntries(), which can provide better performance and readability than traditional loops.
* Considering the use of parallel processing or multi-threading to take advantage of multiple CPU cores.

Overall, this benchmark provides a useful comparison of different approaches to populate an object with values from a range, highlighting the trade-offs between conciseness, readability, and performance.

Related benchmarks:

spread vs mutation vs Object.assign for reduce callback vs for...of loop vs for loop 30K iterations (version: 0)

Comparing performance of: with spread operator vs with mutation vs with object assign vs with for...of loop vs with for loop

Created: 2 years ago by: Registered User

Jump to the latest result

with spread operator

with mutation

with object assign

with for...of loop

with for loop

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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