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Testing123
(version: 0)
testing123
Comparing performance of:
Object.prototype.toString.call vs typeof
Created:
4 years ago
by:
Guest
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Script Preparation code:
var data = 'string'
Tests:
Object.prototype.toString.call
Object.prototype.toString.call(data).slice(8, -1).toLowerCase() === 'string'
typeof
typeof data === 'string'
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
Object.prototype.toString.call
typeof
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 benchmark and explain what is being tested, compared, and analyzed. **Benchmark Overview** The benchmark measures the performance of two different approaches to check if a variable is a string: 1. `typeof data === 'string'` 2. `Object.prototype.toString.call(data).slice(8, -1).toLowerCase() === 'string'` **Comparison of Approaches** There are two main approaches being compared: ### 1. `typeof data === 'string'` This approach uses the `typeof` operator to check the type of the variable `data`. The `typeof` operator returns a string indicating the type of the value, such as `'string'`, `'number'`, etc. **Pros:** * Simple and straightforward * Fast, as it only involves a single operation **Cons:** * May not work correctly for certain types of strings (e.g., internationalized strings) * May be affected by the engine's type inference rules ### 2. `Object.prototype.toString.call(data).slice(8, -1).toLowerCase() === 'string'` This approach uses a more complex method to check if `data` is a string: 1. `Object.prototype.toString.call(data)` calls the `toString()` method on the object `data`, which returns a string representation of the object. 2. `.slice(8, -1)` extracts a substring from the result, starting at index 8 and ending at the second-to-last character. 3. `.toLowerCase()` converts the resulting string to lowercase. 4. The final comparison `=== 'string'` checks if the extracted substring matches the expected string `'string'`. **Pros:** * Works correctly for all types of strings * Avoids potential issues with type inference rules **Cons:** * More complex and slower than the simple `typeof` approach * May be less efficient due to the additional operations involved **Library/Function Usage** In this benchmark, the following functions/libraries are used: * `Object.prototype.toString.call()`: a method call on the built-in `Object.prototype` object. * `String.prototype.toLowerCase()` and `String.prototype.slice()`: methods on the built-in `String` prototype. These functions are part of the JavaScript standard library and are implemented by the engine. **Special JS Feature/Syntax** There is no special JavaScript feature or syntax being used in this benchmark. The focus is solely on comparing two simple string checking approaches. **Other Alternatives** If you were to rewrite a similar benchmark, you might consider using alternative approaches, such as: * Using a library like `assert` to check if the variable is a string * Implementing a custom string checking function that takes into account specific requirements or edge cases * Using a more modern JavaScript feature, such as template literals or `String.prototype.startsWith()`, to simplify the string checking logic.
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