Benchmark: Property vs. Variable Access

Script Preparation code:

var object = {
    prop1: 5,
    prop2: "hello",
    prop3: true
};

var prop1 = 5;
var prop2 = "hello";
var prop3 = true;

Tests:

Variable Access
const result1 = Math.round(prop1); const result2 = prop2.substring(2); const result3 = prop3 && false;
Property Access
const result1 = Math.round(object.prop1); const result2 = object.prop2.substring(2); const result3 = object.prop3 && false;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Variable Access
Property Access

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

**Overview of the Benchmark**

The provided JSON represents a JavaScript microbenchmark that measures the performance difference between accessing properties and variables in an object.

**What is tested?**

In this benchmark, two test cases are compared:

1. **Variable Access**: The code uses variable declarations (`var`) to assign values to `prop1`, `prop2`, and `prop3`. These variables are then used within arithmetic operations (e.g., `Math.round(prop1)`) and string manipulation (e.g., `prop2.substring(2)`).
2. **Property Access**: The code uses object notation (`object.propName`) to access the properties of an object. This object is created using a JSON literal.

**Options compared**

The benchmark compares two approaches:

1. **Variable Access** (`var` declarations)
2. **Property Access** (object notation)

**Pros and Cons**

* **Variable Access**:
	+ Pros: Variables are often more intuitive and easier to understand, especially for developers familiar with traditional JavaScript.
	+ Cons: Variable declarations can lead to slower execution due to the creation of new scope objects and the need to look up variable values by name.
* **Property Access** (object notation):
	+ Pros: Object notation can be faster since property access is a direct lookup operation, without the need for scoping and variable resolution. Additionally, it's often more concise and expressive.
	+ Cons: Property access may require more effort to understand and maintain, especially when dealing with complex object hierarchies.

**Other considerations**

* **Lazy evaluation**: In both approaches, some operations (e.g., `Math.round(prop1)`) are only evaluated when their results are actually needed. This can lead to performance improvements in certain scenarios.
* **Type coercion**: When using property access (`object.propName`), the value of the property is coerced into a number if it's not already one, which can affect performance.

**Library usage**

None of the provided benchmark code uses external libraries or frameworks that would impact its execution. However, some browsers (like Chrome) might include internal optimizations or caching mechanisms that could influence the results of this benchmark.

**Special JS feature**

No special JavaScript features or syntax are used in this benchmark.

**Alternatives**

Other alternatives to measure the performance difference between variable access and property access could involve:

1. Using a different JavaScript engine or compiler, such as V8 or SpiderMonkey.
2. Employing alternative data structures, like arrays or linked lists, instead of objects.
3. Adding more complex operations (e.g., nested loops, recursive functions) to both test cases.

Keep in mind that microbenchmarks often focus on specific, well-controlled scenarios, and variations can lead to biased results.

Related benchmarks:

Property vs. Variable Access (version: 0)

Comparing performance of: Variable Access vs Property Access

Created: 5 years ago by: Guest

Jump to the latest result

Variable Access

Property Access

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):