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_.isFunction vs typeof
(version: 0)
Comparing performance of:
_.isFunction vs typeof
Created:
4 years ago
by:
Guest
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HTML Preparation code:
https://cdn.jsdelivr.net/combine/npm/lodash@4.17.21,npm/lodash@4.17.21/isFunction.min.js
Tests:
_.isFunction
function x() { console.log('xyz'); }; console.log(_.isFunction(x));
typeof
function x() { console.log('xyz'); }; console.log(typeof x === 'function');
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
_.isFunction
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 provided benchmark and explain what's being tested. **Benchmark Definition** The benchmark is comparing two approaches to check if a function exists: `_.isFunction` (from the Lodash library) and `typeof` (a built-in JavaScript operator). **Options Compared** 1. **_.isFunction**: This method returns a boolean indicating whether a given value is a function. 2. **typeof**: This operator returns a string describing the type of a variable, which can include "function" if the variable is a function. **Pros and Cons** * **_.isFunction**: + Pros: More explicit and readable way to check for functions, less prone to errors due to the string value returned. + Cons: Requires importing the Lodash library, may be slower due to the overhead of a library function call. * **typeof**: + Pros: Faster and more lightweight, doesn't require importing any libraries. + Cons: Less explicit and readable, can lead to errors if not used correctly (e.g., comparing strings with functions). **Library - Lodash** Lodash is a popular utility library for JavaScript that provides various helper functions, including `_.isFunction`. This function returns the first element of an array or null if it's empty. In this benchmark, Lodash is imported and used to check if a function exists. **Special JS Feature/Syntax** None mentioned in this specific benchmark. **Other Considerations** When using `typeof` to check for functions, be aware that it also returns "object" for constructor functions (e.g., `new Date()`), which might not be desirable behavior. In contrast, `_isFunction` specifically checks if the value is a function. **Alternatives** If you don't want to use a library or prefer a more lightweight approach, you can simply use the `typeof` operator and check for "function" in the result string using a regular expression (e.g., `/.^function/.test(typeof x)`). However, this approach may lead to errors if not used correctly. In general, for most purposes, both approaches are suitable. If readability and explicitness are crucial, `_isFunction` might be a better choice. If speed and lightweight execution are important, `typeof` could be the way to go.
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