Benchmark: String Constructor vs toString

Script Preparation code:

function usingConstructor(values) {
   return values.map(String); 
}

function usingToString(values) {
   return values.map(v => v.toString()); 
}

Tests:

String()
usingConstructor([42, "42"])
toString()
usingToString([42, "42"])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String()
toString()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 18 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:151.0) Gecko/20100101 Firefox/151.0

Browser/OS: Firefox 151 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
String()	40749716.0 Ops/sec
toString()	38037944.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared, and discussed.

**Benchmark Overview**

The test compares two approaches to concatenate strings in JavaScript:

1. Using the `String` constructor (`new String(value)`).
2. Using the `toString()` method (i.e., calling `value.toString()` directly).

**Test Scenarios**

Two individual test cases are provided:

1. "String()" - This test case uses the first approach, where `String` is used as a function to create an object from the input values `[42, "42"]`. The benchmark measures how long it takes to execute this code.
2. "toString()" - This test case uses the second approach, where `toString()` is called directly on each value in the input array `[42, "42"]`.

**Comparison**

The comparison aims to determine which approach is faster for string concatenation.

**Pros and Cons of Each Approach:**

1. **Using `String` constructor (`new String(value)`):**
	* Pros:
		+ Creates a new object with the desired value, potentially allowing for more flexibility in subsequent operations.
		+ May be necessary when working with legacy code or specific libraries that rely on this approach.
	* Cons:
		+ Creates an unnecessary object, which can lead to higher memory usage and slower execution times due to object creation and garbage collection.
		+ The `String` constructor is generally slower than using the `toString()` method directly.
2. **Using `toString()` method:**
	* Pros:
		+ Faster execution time since it directly calls a built-in method, bypassing object creation.
		+ More memory-efficient since no additional objects are created.
	* Cons:
		+ May not work as expected when used with certain libraries or code that expects a specific type of object.

**Library and Special Features:**

Neither test case uses any external libraries. There are no special JavaScript features mentioned in the provided benchmark code.

**Alternatives:**

Other ways to concatenate strings in JavaScript include:

* Using template literals (`"Hello, ${name}!"`)
* Utilizing string concatenation operators (`+` or `+=`)
* Leveraging the `join()` method with an array of strings

Keep in mind that these alternatives might have different performance characteristics depending on the specific use case and environment.

I hope this explanation helps you understand the benchmark and its implications!

Related benchmarks:

String Constructor vs toString (version: 0)

Comparing performance of: String() vs toString()

Created: 2 years ago by: Guest

Jump to the latest result

String()

toString()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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