Benchmark: Testing field access vs var variable

Script Preparation code:

var x = {a: 42}
var y = {b: 0}
var a = 43
var b = 0

Tests:

test field
while (true) { if (x.a) break }
test variable
while (true) { if (a) break }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
test field
test variable

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):

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**Benchmark Definition**

The benchmark measures two different approaches to accessing variables or object fields in JavaScript:

1. **Field access**: This approach uses dot notation (e.g., `x.a`) to access an object's property.
2. **Variable access**: This approach uses a variable name (e.g., `a`) to access a value.

**Options Compared**

The benchmark compares the performance of these two approaches:

* Field access (`test field`)
* Variable access (`test variable`)

**Pros and Cons**

1. **Field access (`test field`)**:
	* Pros: Can be more readable, especially for accessing properties that are not directly related to variables.
	* Cons: May have overhead due to the dot notation syntax, which can lead to slower performance compared to using a variable name.
2. **Variable access (`test variable`)**:
	* Pros: Can be faster due to the lack of overhead from dot notation, as the compiler/interpreter can directly use the stored value in memory.
	* Cons: May make code less readable, especially when accessing properties that are not related to variables.

**Library and Special JS Feature**

There is no explicit library mentioned in the benchmark definition or individual test cases. However, it's worth noting that some JavaScript engines (like V8) use a feature called " property access" which can lead to faster performance than variable access for certain use cases.

**Special JS Feature**

The `break` statement is used in both benchmark definitions, but not explicitly mentioned as a special feature. The `break` statement is simply a way to exit the loop.

**Other Alternatives**

In general, other approaches to accessing variables or object fields could be:

* Using bracket notation (`x['a']`) for property access
* Using the `in` operator (`'a' in x`) for property existence checks
* Hardcoding variable names (e.g., using a constant) instead of accessing them dynamically

Keep in mind that these alternatives might not be relevant to the specific benchmark or use case, and the chosen approach will depend on the trade-offs between readability, maintainability, and performance.

Related benchmarks:

Testing field access vs var variable (version: 0)

Test accessing an object field vs accessing a variable

Comparing performance of: test field vs test variable

Created: 4 years ago by: Registered User

Jump to the latest result

test field

test variable

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):