Benchmark: isFunction vs typeof function 2

HTML Preparation code:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.core.js"></script>

Tests:

isFunction
const onClose = () => { console.log('hey') } const isfunc = _.isFunction(onClose);
typeof function
const onClose = () => { console.log('hey') } const isfunc = typeof onClose === 'function';

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
isFunction
typeof function

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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Let's break down the provided JSON data and explain what is being tested, the options compared, pros and cons of each approach, and other considerations.

**Benchmark Definition**

The benchmark definition represents a JavaScript microbenchmark that compares two different methods to check if a value is a function. The definition specifies:

* A name for the benchmark: "isFunction vs typeof function 2"
* A description of the benchmark: "isFunction vs typeof function"
* An empty script preparation code section, which means no specific setup or initialization code is required
* An HTML preparation code section that includes a link to include the Lodash library, which provides the `_.isFunction` function used in one of the test cases

**Individual Test Cases**

There are two individual test cases:

1. **"isFunction"`**
	* This test case uses the `_.isFunction` function from Lodash to check if the `onClose` variable is a function.
	* The `_.isFunction` function takes a single argument (in this case, `onClose`) and returns a boolean value indicating whether the argument is a function.
2. **"typeof function"`**
	* This test case uses the `typeof` operator to check if the `onClose` variable is a "function".
	* The `typeof` operator takes a single argument (in this case, `onClose`) and returns a string value indicating the type of the argument (e.g., "function", "number", etc.).

**Pros and Cons**

Here are some pros and cons for each approach:

1. **`.isFunction()`**
	* Pros:
		+ More accurate, as it checks if the value is a function object with a `name` property.
		+ Less prone to false positives (e.g., when checking strings that resemble functions)
	* Cons:
		+ May be slower than using `typeof`, as it involves calling a separate function
		+ Requires the Lodash library, which may add overhead
2. **`typeof function`**
	* Pros:
		+ Faster and more lightweight, as it only uses built-in operators
		+ No additional libraries or dependencies required
	* Cons:
		+ May return false positives (e.g., when checking strings that resemble functions)
		+ Less accurate than `_.isFunction()`

**Other Considerations**

1. **Browser Variability**: The benchmark results are specific to the Chrome 89 browser on Windows Desktop. The results may vary significantly in other browsers or platforms.
2. **Lodash Library Overhead**: The inclusion of the Lodash library adds overhead to the benchmark, which could affect the raw execution time measurements.

**Alternatives**

If you want to compare these approaches with others, here are some alternatives:

1. Use `Function.prototype.toString()` instead of `_.isFunction()`. This approach is similar to using `typeof function`, but it provides more accurate results.
2. Compare with other string checking methods, such as `String.prototype.startsWith('f')` or `String.prototype.endsWith('function')`. These approaches may be faster than using `typeof function`.
3. Use a different library or implementation that provides a more accurate and efficient way to check if a value is a function.

Keep in mind that the choice of approach depends on the specific requirements and constraints of your use case.

Related benchmarks:

isFunction vs typeof function 2 (version: 0)

isFunction vs typeof function

Comparing performance of: isFunction vs typeof function

Created: 7 years ago by: Guest

Jump to the latest result

isFunction

typeof function

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):