Benchmark: object key vs indexof

Script Preparation code:

var a = [{"id":7,"h":76},{"id":4,"h":34},{"id":9,"h":89}];
var b = [];
for(var i=0;i<a.length;i++)b[i] = a[i].id;

Tests:

a
return "wot"
b
return "tow"

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
a
b

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

I'd be happy to help you understand the JavaScript microbenchmark on MeasureThat.net.

**Benchmark Overview**

The benchmark compares two approaches: using an object key (e.g., `a[i].id`) versus using the `indexOf()` method to access the value of an element in a JavaScript array. The test aims to determine which approach is faster for accessing elements in an array.

**Options Compared**

1. **Object Key**: Accessing an element's property directly using its key (e.g., `a[i].id`).
2. **indexOf() Method**: Using the `indexOf()` method to find the index of a specific value in the array and then accessing the element at that index (e.g., `b[i] = a[i].id; b.indexOf(a[i].id) !== -1 ? b[i] : undefined;`).

**Pros and Cons**

* **Object Key**:
	+ Pros: Typically faster since it involves direct property access, which is optimized by the JavaScript engine.
	+ Cons: May not work as expected for arrays with duplicate values or NaN (Not a Number) properties.
* **indexOf() Method**:
	+ Pros: More flexible and works even if there are duplicate values or NaN properties. However, it may involve additional overhead due to string comparison and array search.
	+ Cons: Typically slower since it involves an extra step of searching for the value in the array.

**Other Considerations**

* **Array Iteration**: Both approaches iterate over the array elements. However, `indexOf()` method requires a separate operation to access the element at the found index, which might add unnecessary overhead.
* **Null and Undefined Values**: In the provided test case, no null or undefined values are present in the array. However, in general, if these values can occur, they may affect the performance of both approaches.

**Library**

In the provided benchmark code, no external library is used besides built-in JavaScript features. No third-party libraries like Lodash or Ramda are imported.

**Special JS Features**

There are no special JavaScript features or syntaxes mentioned in this test case. The focus is on comparing two fundamental ways of accessing array elements.

**Alternatives**

Other alternatives to compare when benchmarking array access could include:

1. **Array.prototype.forEach()**: Instead of using a traditional loop, `forEach()` can be used with an arrow function.
2. **Array.prototype.map()**: This method creates a new array by mapping each element in the original array, which might not be relevant for simple access scenarios but can be useful when dealing with transformations or filtering.
3. **Using a custom function to find the index**: Instead of using `indexOf()` method, a custom function could be implemented to search for an element in the array.

These alternatives would require careful consideration of their performance impact and relevance to the specific use case being tested.

Related benchmarks:

object key vs indexof (version: 0)

Comparing performance of: a vs b

Created: 9 years ago by: Guest

Jump to the latest result

a

b

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):