Benchmark: Object key access vs array access

Script Preparation code:

var items = Array.from(Array(1000), (_,x) => ({key: x, value: x*10}));

var objContainer = {};
var arrContainer = [];

for (let i = 100; i >= 0; i--) {
  const index = Math.floor(Math.random() * 1000);
  const item = items[index];
  objContainer[item.key] = item;
  arrContainer.push(item)
}

Tests:

Object access
for (let i = 100; i >= 0; i--) { objContainer[i] }
Array index
for (let i = 100; i >= 0; i--) { arrContainer[i] }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object access
Array index

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided benchmark definition and test cases.

**Benchmark Definition**

The benchmark is designed to compare the speed of accessing an object by key versus accessing an array by index. The script preparation code creates an array of 1000 objects, each with a unique key-value pair, and then populates two containers: `objContainer` (an object) and `arrContainer` (an array). The benchmark then iterates over the range from 100 to 0, randomly selecting an index from `items` and assigning the corresponding item to either `objContainer[key]` or `arrContainer[index]`. This creates a large number of accesses to each data structure.

**Options Compared**

There are two options being compared:

1. **Object access**: accessing an object by key (`objContainer[key]`)
2. **Array index**: accessing an array by index (`arrContainer[index]`)

**Pros and Cons of Each Approach**

* **Object Access**
	+ Pros:
		- Can be faster for certain use cases (e.g., when the object keys are sequential or have a specific pattern).
		- Often more intuitive and easier to read.
	+ Cons:
		- Can be slower due to the overhead of looking up keys in an object.
		- May not perform as well for large numbers of accesses, as objects become increasingly sparse.
* **Array Index**
	+ Pros:
		- Typically faster for random or sequential access patterns.
		- More efficient for large arrays.
	+ Cons:
		- Can be less intuitive and harder to read.
		- May require more memory for the array index.

**Library Used**

There is no library explicitly mentioned in the benchmark definition. However, the `Array.from()` method is used to create an array, which is a built-in JavaScript function.

**Special JS Feature or Syntax**

None are mentioned in this specific benchmark.

**Other Considerations**

* The benchmark uses a randomization factor by selecting a random index from the 1000 items on each iteration. This helps to distribute the load and simulate real-world usage patterns.
* The use of `Array.from()` to create an array is a modern JavaScript feature, introduced in ECMAScript 2015.

**Alternatives**

If you were to rewrite this benchmark, you might consider using alternative data structures or access methods, such as:

* Using a hash table instead of an object for the key-based accesses.
* Implementing a custom caching mechanism to reduce the overhead of repeated accesses.
* Utilizing other optimization techniques, such as parallel processing or memoization.

Keep in mind that the choice of approach depends on the specific use case and requirements.

Related benchmarks:

Object key access vs array access (version: 0)

Test speed of object access by key vs array index

Comparing performance of: Object access vs Array index

Created: 3 years ago by: Guest

Jump to the latest result

Object access

Array index

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):