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constructor comparison vs. instanceof vs Array.isArray 3
(version: 0)
Compares the performance of comparing a constructor strictly to a function object, using the instanceof operator and calling Array.isArray
Comparing performance of:
constructor comparison vs instanceof operator vs Array.isArray call
Created:
4 years ago
by:
Guest
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Script Preparation code:
array = []
Tests:
constructor comparison
array.constructor === Array
instanceof operator
array instanceof Array
Array.isArray call
Array.isArray(array)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
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Test case name
Result
constructor comparison
instanceof operator
Array.isArray call
Fastest:
N/A
Slowest:
N/A
Latest run results:
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'd be happy to explain the benchmark and its options. **Benchmark Overview** The benchmark is designed to compare the performance of three different approaches for comparing an object's constructor with another function object: 1. `array.constructor === Array` 2. `array instanceof Array` 3. `Array.isArray(array)` **Options Compared** The benchmark compares the execution time (in executions per second) of each option on a test case where an array is created and compared to itself using each of the three options. **Pros and Cons of Each Approach:** 1. **`array.constructor === Array`** * Pros: This approach is often considered the most straightforward way to compare objects, as it directly accesses the constructor property. * Cons: It may not be as efficient as other approaches, especially for large arrays or complex constructors. 2. **`array instanceof Array`** * Pros: This approach is more concise and readable than the first option. It's also more intuitive for developers familiar with the `instanceof` operator. * Cons: It may have performance issues due to the overhead of the `instanceof` check, which involves checking if the object's prototype chain matches a specific type. 3. **`Array.isArray(array)`** * Pros: This approach is efficient and well-supported in modern browsers. It avoids the potential performance issues associated with `instanceof`. * Cons: It requires calling an external method (`Array.isArray`) to perform the comparison, which may add overhead. **Library Used** In this benchmark, no libraries are explicitly mentioned. However, it's worth noting that some JavaScript engines or implementations might use internal optimizations or heuristics that could affect the performance of these comparisons. For example, some browsers have optimized `instanceof` checks to avoid unnecessary prototypal lookup. **Special JS Feature/Syntax** The benchmark does not rely on any special JavaScript features or syntax beyond what's commonly used in modern web development (e.g., ES6+ syntax). If you're interested in exploring more advanced features like async/await, generators, or decorators, there might be other benchmarks available that cater to those areas. **Other Alternatives** For comparing objects in JavaScript, some alternative approaches exist: * Using `typeof` with a string literal (e.g., `typeof array === 'object'`) * Utilizing the `constructor.name` property * Implementing custom equality checks or hash functions However, these alternatives are not typically used for simple comparisons like this benchmark. Keep in mind that performance optimizations and internal implementation details can vary significantly between browsers and JavaScript engines. This benchmark provides a useful starting point for comparing different approaches to object comparison, but the actual performance differences may vary depending on your specific use case and environment.
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Array isArray vs instanceof
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constructor comparison vs. instanceof vs Array.isArray 2
instanceof Array vs Array.isArray
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