Benchmark: array of objects assign vs push

Script Preparation code:

var arr = [];

Tests:

new object and assign
for(let i=0; i < 1000; i++) { arr[i] = { i_val: i, i_val2: i+0.001 }; }
array push object
for(let i=0; i < 1000; i++) { arr.push({ i_val: i, i_val2: i+0.001 }); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new object and assign
array push object

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.

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

**Benchmark Definition**

The benchmark is defined in JSON format, specifying the name, description, script preparation code, and HTML preparation code for the benchmark. In this case:

* The "Name" is "array of objects assign vs push".
* The "Description" explains that the benchmark compares two approaches: assigning to an array of objects using the `arr[i] = { ... }` syntax, versus pushing objects onto an array using the `arr.push({ ... })` syntax.
* The "Script Preparation Code" sets up an empty array called `arr`.
* The "HTML Preparation Code" is null, which means that no HTML code needs to be executed before running the benchmark.

**Individual Test Cases**

The benchmark has two individual test cases:

1. **new object and assign**: This test case executes a loop 1000 times, where in each iteration, it assigns a new object to an existing property of the array `arr` using the syntax `arr[i] = { i_val: i, i_val2: i+0.001 }`.
2. **array push object**: This test case executes a loop 1000 times, where in each iteration, it pushes a new object onto the array `arr` using the syntax `arr.push({ i_val: i, i_val2: i+0.001 })`.

**Library Used**

In both test cases, no external library is explicitly used.

**Special JavaScript Features/Syntax**

There are no special JavaScript features or syntax mentioned in this benchmark. Both test cases use standard JavaScript syntax and do not rely on any advanced features like async/await, Promises, or generators.

**Pros and Cons of Different Approaches**

The two approaches being compared have different pros and cons:

* **Assigning to an array using `arr[i] = { ... }`:**
	+ Pros:
		- Can be more efficient for small arrays since it avoids the overhead of pushing a new object onto the array.
		- May be faster for smaller objects or when working with existing properties.
	+ Cons:
		- May lead to unexpected behavior if the property already exists and is not intended to be overwritten.
		- Can result in increased memory usage due to creating multiple copies of the same object.
* **Pushing onto an array using `arr.push({ ... })`**:
	+ Pros:
		- Is more flexible, allowing for dynamic addition of objects without modifying existing properties.
		- Reduces memory usage since only a single copy of the object is created and stored in the array.
	+ Cons:
		- May be slower than assigning to an array due to the overhead of pushing a new object onto the array.
		- Requires more code for dynamic addition, which may lead to increased cognitive load.

**Other Alternatives**

Alternative approaches could include:

* Using `Object.assign()` or `Array.prototype.splice()` methods instead of direct assignment and push operations.
* Comparing the performance of different data structures, such as arrays versus objects, or using a library like Lodash for more efficient array manipulation.

Keep in mind that this benchmark is focused on comparing two specific syntaxes within JavaScript, rather than exploring broader performance differences between various approaches.

Related benchmarks:

array of objects assign vs push (version: 0)

Adding to array of objects assign vs push

Comparing performance of: new object and assign vs array push object

Created: 3 years ago by: Registered User

Jump to the latest result

new object and assign

array push object

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):