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(version: 1)
Comparing performance of:
dot vs bracket
Created:
one year ago
by:
Guest
Go to the latest result
HTML Preparation code:
<!--your preparation HTML code goes here-->
Script Preparation code:
let obj = {a:3}
Tests:
dot
for(let i = 1337;i--;)obj.a+=1
bracket
for(let i = 1337;i--;)obj['a']+=1
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
dot
bracket
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (X11; CrOS x86_64 14695.114.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/102.0.0.0 Safari/537.36
Browser/OS:
Chrome 102 on Chrome OS 14695.114.0
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=587581" width="100%" height="500px"></iframe>
dot
73K/s
bracket
67K/s
View exact numbers
Test name
Executions per second
✓
dot
73,361 Ops/sec
bracket
67,246 Ops/sec
Autogenerated LLM Summary
(model
gpt-4o-mini
, generated one year ago):
The provided benchmark is focused on measuring the performance of property access methods in JavaScript objects. Specifically, it compares two ways to access properties of an object: using dot notation and bracket notation. ### Benchmark Overview - **Benchmark Name**: Property access - **Preparation Code**: The benchmark prepares an object `obj` with a property `a` initialized to `3`. This serves as a common reference point for both types of property access being tested. ### Test Cases The individual test cases perform the same operation (incrementing the value of `obj.a`) but access the property in different ways: 1. **Dot Notation**: - **Benchmark Definition**: `for(let i = 1337;i--;)obj.a += 1` - **Test Name**: "dot" - **Description**: This test accesses the `a` property of the `obj` using dot notation. Dot notation is the simpler and more commonly used method for accessing properties when the property name is known and is a valid identifier. 2. **Bracket Notation**: - **Benchmark Definition**: `for(let i = 1337;i--;)obj['a'] += 1` - **Test Name**: "bracket" - **Description**: This test accesses the property `a` using bracket notation. Bracket notation allows for the property name to be specified as a string, which is useful for dynamically accessing properties or when property names contain special characters or spaces. ### Performance Results The latest benchmark result shows the performance in terms of "executions per second" for each test case: - **Dot Notation**: ~73361 operations/second - **Bracket Notation**: ~67246 operations/second ### Comparison of Approaches #### Pros and Cons - **Dot Notation**: - **Pros**: - More concise and readable. - Generally faster in most environments due to simpler parsing. - **Cons**: - Cannot be used for property names that are not valid identifiers (e.g., containing spaces, special characters, or starting with a number). - **Bracket Notation**: - **Pros**: - More flexible – can reference properties with names that are not valid identifiers. - Useful for dynamic property access (e.g., `obj[propertyName]`). - **Cons**: - Slightly less readable in many cases. - May incur a performance hit compared to dot notation, as seen in the benchmark results. ### Other Considerations - In the benchmark tests, both methods are simple and straightforward; thus, performance differences may be negligible in many real-world scenarios where property access does not represent a performance bottleneck. - For large applications, ensuring that object property access is efficient can be important, especially in performance-critical code paths (e.g., game loops, real-time data processing). ### Alternatives While the benchmark focuses specifically on dot and bracket notations for property access, it is worth noting that other alternatives for managing object properties include: - **Object.defineProperty()**: Allows defining a property with custom attributes (getter/setter, enumerable, configurable). This can be useful for creating more controlled access patterns but is typically slower and more complex than direct access. - **Proxies**: Introduced in ES6, Proxies allow for the creation of a handler object that can redefine fundamental operations on objects, including property access. However, performance may vary based on implementation and use-case. In summary, this benchmark provides clarity on the performance implications of different property access methods in JavaScript, valuable information for developers aiming to write efficient and effective code.
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