Benchmark: For loop with and without conditional length check

Script Preparation code:

var bigArray = [
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {})
];
var mediumArray = [
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {}),
  (() => {})
];
var smallArray = [
  (() => {}),
  (() => {}),
  (() => {})
];
var emptyArray = [];

Tests:

conditional loop
if (bigArray.length) { for (let i = 0; i < bigArray.length; i++) { bigArray[i](); } } if (mediumArray.length) { for (let i = 0; i < mediumArray.length; i++) { mediumArray[i](); } } if (smallArray.length) { for (let i = 0; i < smallArray.length; i++) { smallArray[i](); } } if (emptyArray.length) { for (let i = 0; i < emptyArray.length; i++) { emptyArray[i](); } }
straight loop
for (let i = 0; i < bigArray.length; i++) { bigArray[i](); } for (let i = 0; i < mediumArray.length; i++) { mediumArray[i](); } for (let i = 0; i < smallArray.length; i++) { smallArray[i](); } for (let i = 0; i < emptyArray.length; i++) { emptyArray[i](); }
straight loop with shared index variable
let i; for (i = 0; i < bigArray.length; i++) { bigArray[i](); } for (i = 0; i < mediumArray.length; i++) { mediumArray[i](); } for (i = 0; i < smallArray.length; i++) { smallArray[i](); } for (i = 0; i < emptyArray.length; i++) { emptyArray[i](); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
conditional loop
straight loop
straight loop with shared index variable

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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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 execution time of three different approaches for iterating over arrays: conditional loops, straight loops, and straight loops with shared index variable. The benchmark compares the performance of these approaches on an array with varying lengths (bigArray, mediumArray, smallArray) and an empty array (emptyArray).

**Options Compared**

1. **Conditional Loop**: This approach uses `if` statements to check if the array length is greater than 0 before iterating over it.
2. **Straight Loop**: This approach uses a traditional `for` loop without any conditional checks.
3. **Straight Loop with Shared Index Variable**: This approach uses a shared index variable (`i`) to iterate over all arrays.

**Pros and Cons**

1. **Conditional Loop**:
	* Pros: Only executes the code inside the loop if the array is not empty, which can reduce unnecessary computations.
	* Cons: Requires more conditional checks, which can increase overhead due to branching.
2. **Straight Loop**:
	* Pros: Simple and straightforward, with no additional checks required.
	* Cons: Executes the entire loop regardless of the array length, potentially wasting computations for empty arrays.
3. **Straight Loop with Shared Index Variable**:
	* Pros: Similar to traditional straight loops but avoids creating a new variable `i` on each iteration, which can be beneficial for large arrays.
	* Cons: Still executes all iterations, even if the array is empty.

**Library and Special JS Features**

None of the benchmark test cases use any external libraries or special JavaScript features that are not part of the standard language. The focus is solely on comparing the performance of different iteration approaches.

**Other Considerations**

1. **Array Iteration**: The benchmark uses arrays as input, which can affect performance depending on the browser's implementation.
2. **Number of Iterations**: The benchmark executes each loop a fixed number of times (the length of the array), ensuring a consistent workload for all test cases.
3. **Cache Efficiency**: Modern browsers often optimize cache usage to improve performance. This benchmark does not specifically evaluate cache efficiency.

**Alternatives**

1. **Array.prototype.forEach() and Array.prototype.map()**: These methods iterate over arrays in a more modern and efficient way, eliminating the need for explicit loops or conditional checks.
2. **Typed Arrays**: For certain use cases, using typed arrays (e.g., `Int32Array`) can provide better performance due to their optimized implementation.

Keep in mind that these alternatives may not be directly relevant to this specific benchmark, which focuses on comparing traditional loop approaches.

Related benchmarks:

For loop with and without conditional length check (version: 0)

Comparing performance of: conditional loop vs straight loop vs straight loop with shared index variable

Created: 4 years ago by: Guest

Jump to the latest result

conditional loop

straight loop

straight loop with shared index variable

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):