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zzHasOwn1
(version: 0)
Object lookup performance
Comparing performance of:
undefined vs typeof vs in vs hasOwn
Created:
3 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
var obj = { a: 1, b: 2 };
Tests:
undefined
undefined !== obj.d;
typeof
'undefined' !== typeof obj.d;
in
'd' in obj;
hasOwn
Object.hasOwn(obj, 'd');
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (4)
Previous results
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Test case name
Result
undefined
typeof
in
hasOwn
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 provided benchmark and its components. **Benchmark Overview** The given benchmark measures object lookup performance using four different approaches: 1. `undefined` comparison 2. `typeof` check for "undefined" type 3. `"d"` in object (`in` operator) 4. `Object.hasOwn()` method Each approach is tested with a single object literal, `obj`, containing the property `a: 1` and `b: 2`. **Benchmark Definitions** The benchmark definitions are JSON objects that specify: * The name of the benchmark * A brief description of what the benchmark measures (e.g., "Object lookup performance") * Script preparation code to create the object literal, `obj` * HTML preparation code is not provided Each definition also includes a test case definition, which specifies: * A raw UA string representing the browser being tested * The name of the browser and its version (Chrome 108 in this case) * The device platform (Desktop) and operating system (Windows) * Execution frequency per second * Test name (e.g., "typeof") **Comparison of Approaches** 1. `undefined` comparison: * Pros: Simple, fast execution. * Cons: May be optimized away by the browser, making it less accurate. 2. `typeof` check for "undefined" type: * Pros: More accurate and reliable than raw comparisons. * Cons: Can be slower due to the additional type checking. 3. `"d"` in object (`in` operator): * Pros: Fast execution and low overhead. * Cons: May not work as expected if `obj.d` is undefined or null. 4. `Object.hasOwn()` method: * Pros: Accurate and reliable, especially when `obj.d` is undefined or null. * Cons: Can be slower due to the additional function call. **Library Usage** None of the benchmark definitions explicitly use a JavaScript library. **Special JS Features or Syntax** There are no special JavaScript features or syntax used in this benchmark. The code only uses basic object literals and comparisons. **Alternative Approaches** Other alternatives for measuring object lookup performance could include: * Using a different data structure, such as an array or set. * Measuring the execution time of accessing properties using bracket notation (e.g., `obj['d']`). * Using a more complex object with multiple levels of nesting. * Comparing the performance of different browsers or environments. These alternative approaches could provide additional insights into the performance characteristics of each benchmark approach.
Related benchmarks:
typeof first or second
undefined vs hasOwnProperty
zzHasOwn2
undefined vs evaluation vs hasOwnProperty
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