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typeof x === 'number' vs isNaN(x) rtestset22
(version: 0)
Comparing performance of:
typeof vs isNaN
Created:
2 years ago
by:
Guest
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Tests:
typeof
undefined * -1 + '' === 'NaN'
isNaN
isNaN(undefined * -1)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
typeof
isNaN
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and its test cases. **Benchmark Definition** The provided JSON represents a JavaScript microbenchmark created using MeasureThat.net. The main content of this benchmark is defined in two places: 1. **"Name": "typeof x === 'number' vs isNaN(x) rtestset22"`** This line defines the name of the benchmark. It appears to be comparing two different ways to check if a value is NaN (Not a Number): `typeof x === 'number'` and `isNaN(x)`. The suffix `rtestset22` suggests that this is a variant of a previous benchmark, possibly with some changes or modifications made since then. 2. **"Individual test cases"`** The provided code includes two individual test cases: **Test Case 1: "typeof"** * `"Benchmark Definition": "undefined * -1 + '' === 'NaN'"` * `"Test Name": "typeof"` This test case checks if the expression `undefined * -1 + ''` is equal to `'NaN'`. This test case evaluates how the `typeof` operator behaves when applied to an undefined value (`undefined`) and then multiplied by `-1`. **Test Case 2: "isNaN"** * `"Benchmark Definition": "isNaN(undefined * -1)" * `"Test Name": "isNaN"` This test case checks if the expression `NaN(undefined * -1)` is true. This test case evaluates how the `isNaN()` function behaves when applied to a value that results from multiplying `undefined` by `-1`. **Library and Special Features** There are no specific libraries mentioned in the provided benchmark code. As for special JavaScript features or syntax, there isn't any mention of them in this particular example. However, we can still discuss the behavior of these two operators: * The `typeof` operator returns a string indicating the type of the value (e.g., `'number'`, `'string'`, etc.). In this case, it's used to check if the result is not `undefined`. * The `isNaN()` function checks if a value is NaN. It can also take an additional argument to specify how to handle non-numeric values. **Approaches and Considerations** Here are some pros and cons of each approach: 1. **`typeof x === 'number'`** * Pros: * Can be more readable for certain use cases (e.g., checking if a variable is assigned the value `'number'`) * Less prone to subtle errors compared to `isNaN()` * Cons: * May return unexpected results for some values (e.g., non-numeric strings, null, or undefined) 2. **`isNaN(x)`** * Pros: * More concise and expressive * Less prone to subtle errors compared to `typeof` * Cons: * Returns false positives for certain numeric types (e.g., NaN) **Other Alternatives** Some alternative ways to check if a value is NaN in JavaScript include: * Using the `Number.isNaN()` function, which was introduced in ECMAScript 2015. * Creating a custom function or mixin to handle non-numeric values. ```javascript function isNaN(value) { return typeof value === 'number' && isNaN(value); } ``` These alternatives can provide more control and flexibility when working with NaN values, but may also increase code complexity.
Related benchmarks:
typeof x === 'number' vs isNaN(x)
typeof number vs. Number.isNan vs. isNan
typeof x === 'number' vs Number.isNaN(x)
Number.isInteger() vs typeof
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