Benchmark: Object into variable vs Direct object access

Script Preparation code:

var list = {
	test: 1
}

var item = {
	name: 'test'
}

var count = 1000

Tests:

Store into variable
var isChecked = Boolean(list[item.name]) for (let i = 0; i < count; i++) { console.log(isChecked) console.log(isChecked) console.log(isChecked) }
Access object
for (let i = 0; i < count; i++) { console.log(Boolean(list[item.name])) console.log(Boolean(list[item.name])) console.log(Boolean(list[item.name])) }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Store into variable
Access object

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36

Browser/OS: Chrome 85 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Store into variable	7.7 Ops/sec
Access object	7.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the benchmark and explore what's being tested.

The provided JSON represents a JavaScript microbenchmark test case on the MeasureThat.net website. The test is designed to measure the performance difference between two approaches: storing the result of an object access in a variable versus directly accessing the property.

**Script Preparation Code**
```javascript
var list = {
  test: 1
};

var item = {
  name: 'test'
};

var count = 1000;
```
This code sets up an object `list` with a single property `test` and initializes another object `item` with a `name` property. The variable `count` is set to 1000, which will be used in the benchmark.

**Benchmark Definition**
```javascript
var isChecked = Boolean(list[item.name]);

for (let i = 0; i < count; i++) {
  console.log(isChecked);
  console.log(isChecked);
  console.log(isChecked);
}
```
This code defines a variable `isChecked` and assigns it the result of accessing the `name` property on the `item` object using the `Boolean()` function. The benchmark then loops 1000 times, logging the value of `isChecked` to the console three times in each iteration.

**Alternative Approach**
```javascript
for (let i = 0; i < count; i++) {
  console.log(Boolean(list[item.name]));
  console.log(Boolean(list[item.name]));
  console.log(Boolean(list[item.name]));
}
```
This code is similar to the first approach, but instead of storing the result in a variable, it directly logs the result of `Boolean(list[item.name])` to the console three times.

**Comparison**
The two approaches are compared to determine which one is faster. The benchmark measures the number of executions per second (ExecutionsPerSecond) for each test case, providing an indication of performance difference between the two methods.

**Pros and Cons**

* **Storing in a variable (`isChecked`):**
	+ Pros:
		- Cache locality: Accessing `list[item.name]` multiple times is likely to hit the cache, reducing the number of memory accesses.
		- Simplified code: The logic is more concise and easier to read.
	+ Cons:
		- Potential overhead of assigning a new value to `isChecked` on each iteration (although unlikely significant in this case).
* **Direct property access (`Boolean(list[item.name])`):**
	+ Pros:
		- Eliminates the need for an extra variable, potentially reducing memory allocation and deallocation overhead.
	+ Cons:
		- May not hit the cache as effectively due to the repeated memory accesses.

**Other Considerations**

* The use of `Boolean()` function is likely used to ensure that the result is a boolean value, which may have performance implications depending on the specific JavaScript engine and version being tested.
* The benchmark only measures the execution speed of these two approaches and does not account for other factors like code readability, maintainability, or scalability.

**Library Used**

There is no explicit library mentioned in the benchmark definition. However, some JavaScript engines (e.g., V8) may provide built-in optimizations or features that could affect the performance of this code.

**Special JS Feature/Syntax**

The benchmark does not use any special JavaScript features or syntax beyond what's commonly available in most modern JavaScript engines.

**Alternatives**

If you're interested in exploring alternative approaches, some possibilities include:

* Using a different method for accessing `list[item.name]`, such as using bracket notation (`list['name']`) or the `in` operator.
* Adding more variables or logic to the benchmark to test additional aspects of performance.
* Using a different type of loop (e.g., `while` instead of `for`) or iteration method (e.g., `setInterval()`) to see how it affects the results.

Related benchmarks:

Object into variable vs Direct object access (version: 0)

Comparing performance of: Store into variable vs Access object

Created: 4 years ago by: Guest

Jump to the latest result

Store into variable

Access object

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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