Benchmark: object vs array for non-consecutive indices

Tests:

Object
var obj = {}; obj[4] = 20; obj[10] = 21; obj[60] = 22; obj[31] = 23; obj[6] = 24; obj[23] = 25; obj[41] = 26; obj[33] = 27; obj[58] = 28; obj[4]; obj[22]; obj[21]; obj[55]; obj[60]; obj[48]; obj[33]; obj[11]; obj[1];
Array
var obj = []; obj[4] = 20; obj[10] = 21; obj[60] = 22; obj[31] = 23; obj[6] = 24; obj[23] = 25; obj[41] = 26; obj[33] = 27; obj[58] = 28; obj[4]; obj[22]; obj[21]; obj[55]; obj[60]; obj[48]; obj[33]; obj[11]; obj[1];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object
Array

Fastest: N/A

Slowest: N/A

Latest run results:

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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 and explain what's being tested, compared, and considered.

**Benchmark Purpose:**

The test is designed to compare the performance of accessing elements at non-consecutive indices in two data structures: objects and arrays.

**Options Compared:**

There are two approaches:

1. **Objects:** Accessing elements using object notation (e.g., `obj[4]`, `obj[22]`).
2. **Arrays:** Accessing elements using array notation (e.g., `obj[4]`, `obj[22]`) in a JavaScript array (`var obj = [];`).

**Pros and Cons of Each Approach:**

* **Objects:**
	+ Pros:
		- Can be more readable and expressive for some use cases.
		- Allows for dynamic property names, which can be useful in certain situations.
	+ Cons:
		- Can lead to slower performance due to the overhead of looking up properties using the bracket notation (`obj[4]`).
		- May require more memory allocation and deallocation compared to arrays.
* **Arrays:**
	+ Pros:
		- Generally faster than object notation, as it allows for direct indexing (e.g., `obj[4]`).
		- Less memory overhead compared to objects.
	+ Cons:
		- Can lead to less readable code if not used carefully.

**Library and Purpose:**

In the provided benchmark definition, a JavaScript array is declared using the `var obj = []` syntax. The purpose of this library (the `[]` notation) is to create an empty array that can be used as a collection of values, which are accessed at non-consecutive indices in the test.

**Special JS Features/Syntax:**

None mentioned in the provided benchmark definition.

**Other Considerations:**

1. **Cache Locality:** The access pattern used in this benchmark (accessing elements at non-consecutive indices) is likely to benefit from cache locality, which can improve performance by reducing the number of memory accesses.
2. **Memory Allocation and Deallocation:** The use of objects with bracket notation may lead to more frequent memory allocation and deallocation compared to arrays, which could impact performance.

**Alternative Approaches:**

Other alternatives for accessing elements at non-consecutive indices include:

1. **Dense Arrays:** Using dense arrays (e.g., `var obj = new Int32Array([20, 21, ...])`) can provide faster access times compared to sparse arrays or objects.
2. **Native Web Workers:** Utilizing native web workers (e.g., using the `WebWorkerAPI`) can offload computationally intensive tasks and improve performance.
3. **SIMD Instructions:** Leveraging SIMD (Single Instruction, Multiple Data) instructions (e.g., using AVX-512) can accelerate certain operations and reduce the number of iterations required for benchmarking.

Keep in mind that these alternatives may require additional setup, dependencies, or expertise to implement effectively.

Related benchmarks:

object vs array for non-consecutive indices (version: 0)

Comparing performance of: Object vs Array

Created: 3 years ago by: Guest

Jump to the latest result

Object

Array

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):