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In operator vs Object Accessors
(version: 0)
Comparing performance of:
in vs Object accessor
Created:
5 years ago
by:
Guest
Go to the latest result
Tests:
in
const a = { b: "c" } if ("b" in a) { console.log(a.b) }
Object accessor
const a = { b: "c" } if (a.b) { console.log(a.b) }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
in
Object accessor
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36
Browser/OS:
Chrome 129 on Windows
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<iframe src="https://measurethat.net/Embed?id=558987" width="100%" height="500px"></iframe>
Object accessor
353K/s
in
210K/s
View exact numbers
Test name
Executions per second
✓
Object accessor
353,293 Ops/sec
in
210,458 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided JSON data and explain what's being tested. **Benchmark Definition** The benchmark definition is a simple JavaScript snippet that tests two different approaches to accessing property values in an object: 1. **`in` operator**: This approach uses the `in` keyword to check if a key exists in an object. 2. **Object Accessors**: This approach uses dot notation (`a.b`) or bracket notation (`a['b']`) to access property values directly. **Options being compared** The benchmark is comparing two options: 1. Using the `in` operator 2. Using object accessors (dot notation and bracket notation) **Pros and Cons of each approach** * **`in` operator**: + Pros: - Fast and efficient, as it only requires a single lookup operation. - Portable across different browsers and environments. - Cons: - May not work as expected in certain edge cases (e.g., when the object has multiple properties with the same key). - Can be slower than other approaches due to the additional overhead of the lookup operation. * **Object Accessors**: + Pros: - Typically faster and more efficient than the `in` operator, as it involves a single property access operation. - More readable and intuitive for many developers. + Cons: - May not work in older browsers or environments that don't support dot notation and bracket notation. **Library usage** Neither of the benchmarked code snippets uses any external libraries. The `in` operator is a built-in JavaScript keyword, while object accessors are part of the language itself. **Special JS feature or syntax** There is no special JavaScript feature or syntax being used in these benchmarks. Both approaches rely on standard JavaScript syntax and features. **Other alternatives** If you wanted to test other options, you could consider adding additional benchmark cases that explore different approaches, such as: * Using property names with bracket notation (e.g., `a['b']`) * Using the `hasOwnProperty` method to check if a key exists in an object * Using a custom function or helper to perform property access However, for this specific benchmark, the focus is on comparing the performance of the `in` operator versus object accessors.
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