Benchmark: Instanceof VS toString for date comparison

Tests:

instanceof
'a' instanceof Date
toString
Object.prototype.toString.call('a')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
instanceof
toString

Fastest: N/A

Slowest: N/A

Autogenerated LLM Sumamry (model llama3.2:3b, generated 3 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

MeasureThat.net is testing two different approaches to compare dates in JavaScript:

1. `instanceof Date`: This approach uses the `instanceof` operator to check if a value is an instance of the `Date` object.
2. `Object.prototype.toString.call('a')`: This approach uses the `toString()` method on the `Object.prototype` and passes a string `'a'` as an argument.

**Options being compared**

The two options being compared are:

* Using the `instanceof` operator to check if a value is a `Date` object
* Using the `toString()` method on `Object.prototype` with a string argument

**Pros and Cons of each approach:**

1. `instanceof Date`:
	* Pros:
		+ Directly checks if a value is a `Date` object, which might be more efficient.
		+ Less chance of type coercion errors.
	* Cons:
		+ Can be slower due to the overhead of creating a new `Date` object for comparison.
		+ Might not work as expected with non-Date values (e.g., strings).
2. `Object.prototype.toString.call('a')`:
	* Pros:
		+ More flexible and can handle various types of values, including strings and numbers.
		+ Less chance of type coercion errors.
	* Cons:
		+ Can be slower due to the overhead of calling a method on `Object.prototype`.
		+ Might not work as expected with non-String values (e.g., arrays or objects).

**Other considerations:**

* Both approaches assume that the input value is a string representation of a date. If the input can be a `Date` object itself, the results might differ.
* The `instanceof` operator uses a cached lookup table for performance, which might affect its behavior in certain cases.

**Library usage: None**

There are no libraries used in these benchmark tests.

**Special JavaScript feature or syntax: None**

There are no special features or syntax used in this benchmark. It's a straightforward comparison of two approaches.

**Other alternatives:**

If you need to compare dates, other alternatives might include:

* Using the `Date.parse()` method to convert strings to timestamps
* Using the `Date.now()` method to get the current timestamp
* Using a date parsing library like Moment.js or Luxon

In terms of comparing values using the `instanceof` operator and `toString()` method, other approaches might include:

* Using the `TypeOf` operator (not available in all browsers)
* Using a custom implementation for type checking

However, these alternatives are not directly related to the specific benchmark test being discussed.

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36

Browser/OS: Chrome 128 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
instanceof	20134030.0 Ops/sec
toString	17093920.0 Ops/sec

Related benchmarks:

Instanceof VS toString for date comparison (version: 0)

Comparing performance of: instanceof vs toString

Created: one month ago by: Guest

Jump to the latest result

instanceof

toString

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Sumamry (model llama3.2:3b, generated 3 days ago):