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isNaN vs Number.isNaN Boolean
(version: 1)
Comparing performance of:
global isNaN vs method isNaN
Created:
9 months ago
by:
Guest
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Tests:
global isNaN
isNaN(true)
method isNaN
Number.isNaN(true)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
global isNaN
method isNaN
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
9 months ago
)
User agent:
Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/141.0.0.0 Mobile Safari/537.36
Browser/OS:
Chrome Mobile 141 on Android
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<iframe src="https://measurethat.net/Embed?id=619331" width="100%" height="500px"></iframe>
method isNaN
70.8M/s
global isNaN
69.0M/s
View exact numbers
Test name
Executions per second
✓
method isNaN
70,814,344 Ops/sec
global isNaN
68,961,304 Ops/sec
Autogenerated LLM Summary
(model
gpt-4o-mini
, generated 9 months ago):
The benchmark in question compares two functionalities in JavaScript for evaluating whether a value is NaN (Not-a-Number): the global `isNaN` function and the static method `Number.isNaN`. ### Test Cases Overview: 1. **Global `isNaN` function**: - **Test Name**: `global isNaN` - **Benchmark Definition**: `isNaN(true)` - **Purpose**: This test case checks the performance of the standalone `isNaN` function when it receives `true` as an argument. 2. **Static `Number.isNaN` method**: - **Test Name**: `method isNaN` - **Benchmark Definition**: `Number.isNaN(true)` - **Purpose**: This test case evaluates the performance of the `Number.isNaN` method with the same argument (`true`). ### Pros and Cons of Each Approach: #### 1. Global `isNaN`: - **Pros**: - Compatibility: It is a legacy function and available in all JavaScript environments. - Familiarity: Many developers are accustomed to using it since it has been around for a long time. - **Cons**: - Type Coercion: `global isNaN` performs type coercion, meaning it will return `true` for any non-numeric value that cannot be converted to a number (e.g., `isNaN("hello")` returns `true`). - Potential for unexpected results: This can lead to confusion when checking if a value is specifically NaN. #### 2. `Number.isNaN`: - **Pros**: - Precision: `Number.isNaN` does not perform type coercion. It will only return `true` if the argument is precisely the value `NaN`, making it a more reliable option for checking NaN values. - Better performance: Generally, `Number.isNaN` is faster than the global `isNaN` function, especially in cases where the argument can be of various types (this is illustrated by the benchmark performance results). - **Cons**: - Limited compatibility: `Number.isNaN` was introduced in ECMAScript 2015 (ES6), so it may not be supported in very old JavaScript environments. ### Performance Results Analysis: - The benchmark shows that: - `Number.isNaN(true)` has a higher execution rate (`231,519,168.0 executions per second`) compared to `isNaN(true)` with `224,391,904.0 executions per second`. - Both tests were conducted in the same environment (Chrome 141 on Mac OS X 10.15.7), which allows for a fair comparison. ### Alternative Approaches: - **Using `Object.is()`**: Another method to check for NaN could be using `Object.is(value, NaN)`, which is also strict and does not coerce the type. - **Custom utility functions**: Developers can create their own utility functions for checking NaN, but this is usually unnecessary given the existence of the JavaScript built-ins. ### Conclusion: This benchmark effectively highlights the differences between two ways of checking for NaN—one that is traditional with potential pitfalls (global `isNaN`) and a more modern, strict, and performant approach (`Number.isNaN`). Software engineers should consider using `Number.isNaN` in new code to ensure accuracy and potentially better performance when dealing with numeric values.
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