Benchmark: toString vs String Concatenation

Tests:

toString
let num = 500; let nums = []; for(let i = 0; i < 100; ++i) { nums.push(num.toString()); }
String Concatenation
let num = 500; let nums = []; for(let i = 0; i < 100; ++i) { nums.push(''+num); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
toString
String Concatenation

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's dive into explaining the benchmark and its test cases.

**Benchmark Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The provided JSON represents a simple benchmark that compares the performance of two different approaches: `toString` and string concatenation.

**Test Cases**

There are two individual test cases:

1. **`toString`**: This test case uses a loop to push 100 instances of the string representation of the number 500 onto an array (`nums`). The conversion is done using the `toString()` method.
2. **`String Concatenation`**: This test case also uses a loop, but this time it pushes 100 instances of the string literal `'+'` followed by the number 500 onto the same array (`nums`). Note that in JavaScript, `'+'` has a higher precedence than multiplication, so this is equivalent to `5 + 0`. However, I'll explain why this approach is used later.

**Library and Purpose**

In both test cases, there is no specific library being used. The only libraries that might be implicitly involved are the built-in JavaScript arrays (`Array`) and strings (`String`).

**Special JS Feature or Syntax**

The use of `toString()` to convert a number to a string is a fundamental feature of JavaScript. This method is called the "ToString Method" or simply "toNumber()". In this benchmark, it's used to create 100 instances of the same string value, which allows for direct comparison.

**Approaches Compared**

The two approaches compared in this benchmark are:

*   **`toString()`**: Creates 100 identical strings by converting a number (500) to a string using the `toString()` method.
*   **String Concatenation**: Creates 100 strings that have the same numeric value but with different formatting, using the syntax `'+' + num`.

**Pros and Cons of Each Approach**

*   **`toString()`**:
    *   Pros:
        *   Direct conversion from number to string creates identical strings.
        *   Can be faster due to less overhead compared to concatenation methods.
    *   Cons:
        *   Creates an array of identical strings, which might not reflect real-world use cases.

*   **String Concatenation** (`'+' + num`):
    *   Pros:
        *   Reflects more real-world string formatting patterns in JavaScript (e.g., `5+2`).
    *   Cons:
        *   Creates an array of strings with different formats, making it harder to compare.
        *   Can be slower due to the overhead of concatenation operations.

**Why String Concatenation is Used**

The use of `'+' + num` in this benchmark might seem unusual at first. However, consider the following:

*   In JavaScript, when using string concatenation with variables, the variable's value is converted to a string and appended to the original string. This behavior can be leveraged to create a sequence of strings that have the same numeric value but different formatting.

**Other Alternatives**

While not explicitly mentioned in this benchmark, other alternatives for creating arrays of repeated values could include:

*   Using an array method like `Array.prototype.fill()` or `Array.prototype.copyWithin()`.
*   Utilizing libraries or modules that provide optimized string creation functions (e.g., strings with a fixed length).
*   Employing bitwise operations to create repeating byte patterns.

Keep in mind that these alternatives might not be relevant for this specific benchmark and are more suitable for general-purpose string repetition scenarios.

Related benchmarks:

toString vs String Concatenation (version: 0)

Comparing performance of: toString vs String Concatenation

Created: 3 years ago by: Guest

Jump to the latest result

toString

String Concatenation

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):