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instanceof vs typeof function
(version: 0)
Comparing performance of:
instanceof vs typeof
Created:
3 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var fn = function(){return 42}
Tests:
instanceof
fn instanceof Function
typeof
typeof fn === 'function'
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
instanceof
typeof
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
9 months ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/142.0.0.0 Safari/537.36
Browser/OS:
Chrome 142 on Windows
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=620533" width="100%" height="500px"></iframe>
typeof
285.0M/s
instanceof
165.4M/s
View exact numbers
Test name
Executions per second
✓
typeof
284,996,128 Ops/sec
instanceof
165,413,728 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the explanation. The provided JSON represents two individual test cases for measuring the performance of JavaScript microbenchmarks on MeasureThat.net. Here's what each section tests: **Benchmark Definition:** * The first line specifies the name and description of the benchmark, which is "instanceof vs typeof function." * However, there is no actual code to execute; instead, a script preparation code (`var fn = function(){return 42}`) and an html preparation code are provided. This suggests that the benchmark is testing the performance difference between using `instanceof` and `typeof` operators on a specific JavaScript function. **Script Preparation Code:** The script preparation code defines a simple JavaScript function named `fn`, which returns the value `42`. This function will be used as input for both test cases. **Individual Test Cases:** There are two individual test cases: 1. **Test Case 1: "instanceof"** * Benchmark Definition: `fn instanceof Function` * Purpose: To measure the performance of using the `instanceof` operator to check if the function `fn` is an instance of the `Function` constructor. 2. **Test Case 2: "typeof"** * Benchmark Definition: `typeof fn === 'function'` * Purpose: To measure the performance of using the `typeof` operator to check if the variable `fn` is a function. **Pros and Cons:** 1. **Using `instanceof`**: This approach can be more precise for checking if an object is an instance of a specific constructor, but it may incur additional overhead due to the need to search the prototype chain. 2. **Using `typeof`**: This approach is generally faster and more concise, as it only checks the type of the variable without searching the prototype chain. **Library/Functions Used:** None of the test cases use external libraries or functions beyond JavaScript's built-in operators (`instanceof`, `typeof`, and the `Function` constructor). **Special JS Features/Syntax:** There are no specific special features or syntax mentioned in the benchmark. However, it's worth noting that the use of the `===` operator for equality checks is a common feature of modern JavaScript. **Other Alternatives:** If you're interested in measuring performance differences between other methods for checking function types, some alternative approaches could include: * Using a regex to extract the type of the variable (e.g., `/^function/`) * Creating a custom function to check if an object is a certain type * Using a library or framework that provides a more precise way of checking function types Keep in mind that these alternatives may not be as simple or straightforward as using `instanceof` and `typeof`, and their performance characteristics may vary depending on the specific use case.
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