Benchmark: test push + concat in loop versus push a collection + concat with map

Tests:

multiple push + concat in a loop
const result = []; const entries = ["a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a"]; entries.forEach(entry => result.push(entry + "c"));
push destructured array + map concat in one call
const result = []; const entries = ["a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a"]; result.push(...entries.map(e => e + "c"));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
multiple push + concat in a loop
push destructured array + map concat in one call

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:150.0) Gecko/20100101 Firefox/150.0

Browser/OS: Firefox 150 on Linux

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Test name	Executions per second
multiple push + concat in a loop	5419849.0 Ops/sec
push destructured array + map concat in one call	4321263.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and explain what's being tested, the options compared, pros and cons of each approach, and other considerations.

**Benchmark Definition:**
The benchmark tests two different ways to concatenate and push elements onto an array in a loop. The benchmark aims to determine which approach is faster on modern JavaScript engines.

**Test Case 1:** "multiple push + concat in a loop"

In this test case, the script iterates over an array of strings using `forEach` and pushes each string followed by a constant character `'c'` onto another empty array. The resulting array is not used; it's only pushed elements are counted.

**Test Case 2:** "push destructured array + map concat in one call"

In this test case, the script uses an array destructuring assignment to create two arrays: `entries` and `result`. It then maps over `entries`, appending `'c'` to each element using a callback function. The resulting mapped array is directly pushed onto another empty array.

**Options Compared:**

1. **Multiple Push + Concat in Loop**
	* Pros:
		+ This approach uses built-in methods (`push` and `concat`) that are likely optimized by modern JavaScript engines.
	* Cons:
		+ Requires explicit iteration over the array using `forEach`, which can be slower than a single, vectorized operation.
2. **Push Destructured Array + Map Concat in One Call**
	* Pros:
		+ This approach uses an array destructuring assignment to create two arrays and a map function, which is likely faster since it's a more compact and vectorized operation.
	* Cons:
		+ Requires knowledge of array destructuring and the `map` method with callback functions.

**Other Considerations:**

* Both test cases use modern JavaScript features, such as array destructuring (`entries`) and the `forEach` method.
* The benchmark uses a simple loop to iterate over the input array, which is likely optimized by modern JavaScript engines. However, the performance difference between the two approaches might be affected by other factors, like the size of the input array or the specific JavaScript engine used.

**Library/Language Features Used:**

None explicitly mentioned in the benchmark definition.

**Special JS Feature/Syntax:**
The test case uses `forEach` and array destructuring (`entries`) as modern JavaScript features. Additionally, it uses the spread operator (`...`) to concatenate arrays (not directly applicable here but useful in other contexts).

To provide alternative approaches or variations on these tests, you might consider:

1. Using a different loop iteration method, such as `for` instead of `forEach`.
2. Adding more elements to the input array to see how performance scales.
3. Changing the character appended to each element (`'c'`) to observe how the result affects performance.
4. Comparing these results with other JavaScript engines or versions.

Feel free to ask if you'd like me to elaborate on any of these points!

Related benchmarks:

test push + concat in loop versus push a collection + concat with map (version: 1)

Comparing performance of: multiple push + concat in a loop vs push destructured array + map concat in one call

Created: 3 years ago by: Registered User

Jump to the latest result

multiple push + concat in a loop

push destructured array + map concat in one call

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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