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getOwnPropertyNames vs loop vs cached property names
(version: 0)
Comparing performance of:
getOwnPropertyNames vs Cached property names vs for in
Created:
9 years ago
by:
Guest
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Script Preparation code:
var obj = { $names : ['a','b','c'], a:1, b:2, c:3 }
Tests:
getOwnPropertyNames
var ks = Object.getOwnPropertyNames(obj); var n = 0; for (var i = 0; i < ks.length; i++) { var k = obj[ks[i]]; if (k.charAt(0) == '$') continue; n++; }
Cached property names
var ks = obj['$names']; var n = 0; for (var i = 0; i < ks.length; i++) { var k = obj[ks[i]]; n++; }
for in
var n = 0; for (var k in obj) { if (k.charAt(0) == '$') continue; n++; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
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Test case name
Result
getOwnPropertyNames
Cached property names
for in
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the benchmark and its test cases. **What is being tested?** The benchmark is designed to compare three approaches for iterating over an object's properties: 1. **`Object.getOwnPropertyNames()`**: This method returns an array of strings representing the names of all properties (including inherited ones) that are directly accessible on an object. 2. **Cached property names**: In this approach, we assume that some libraries or frameworks provide a cached list of property names for an object, which is then used to iterate over the properties. 3. **`for...in` loop with filtering**: This approach uses the `for...in` loop to iterate over all properties of an object and skips any properties whose name starts with a dollar sign (`$`). **Options comparison** The three approaches have different pros and cons: * **`Object.getOwnPropertyNames()`**: + Pros: Simple, straightforward, and efficient. + Cons: May include inherited properties, which can be slow to iterate over for large objects. * **Cached property names**: + Pros: Can be faster than `getOwnPropertyNames()` if the cached list is already available. + Cons: Assumes that a library or framework provides the cached list, which may not always be the case. + Pros (if implemented correctly): Avoids iterating over inherited properties and can be optimized for large objects. + Cons (if implemented incorrectly): May still include inherited properties or introduce additional overhead. * **`for...in` loop with filtering**: + Pros: Flexible, as it allows filtering out properties based on their names. + Cons: Can be slower than `getOwnPropertyNames()` and cached property names if not optimized. The `for...in` loop approach is currently the fastest, but this might change depending on the specific implementation and browser optimizations. **Library considerations** The benchmark uses the `Object.getOwnPropertyNames()` method, which is a standard JavaScript method. No external libraries are required for these test cases. **Special JS features or syntax** There are no special JavaScript features or syntax used in these test cases. **Other alternatives** If you wanted to include other approaches in your benchmark, some alternative methods for iterating over an object's properties could be: * Using `Object.keys()` (which returns only own enumerable properties) and then filtering out properties whose names start with a dollar sign. * Using a custom iteration function or a recursive approach. * Comparing performance of using `for...in`, `for...of` (if supported), or other iteration methods. Keep in mind that each alternative method has its pros and cons, and the best choice depends on your specific use case and requirements.
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