Benchmark: String() vs .toString() vs + vs ES6

Tests:

String()
let num = 500; let nums = []; for (let i = 0; i < 1000; i++) { nums.push(String(num)); }
.toString()
let num = 500; let nums = []; for (let i = 0; i < 1000; i++) { nums.push(num.toString()); }
Plus string
let num = 500; let nums = []; for (let i = 0; i < 1000; i++) { nums.push(num + ''); }
String plus
let num = 500; let nums = []; for (let i = 0; i < 1000; i++) { nums.push('' + num); }
ES6
let num = 500; let nums = []; for (let i = 0; i < 1000; i++) { nums.push(`${num}`); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String()
.toString()
Plus string
String plus
ES6

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Windows

View result in a separate tab

Test name	Executions per second
String()	10686.8 Ops/sec
.toString()	129030.5 Ops/sec
Plus string	336617.2 Ops/sec
String plus	320945.5 Ops/sec
ES6	357746.6 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The provided JSON defines a benchmark with four test cases:

1. **`"String()"`**: This test case creates an empty array `nums` and pushes the string representation of a number 500 to it 1000 times.
2. **`".toString()"`**: Similar to the first test case, but uses the `.toString()` method to convert the number to a string instead of the built-in `String()` function.
3. **`"Plus string"`**: This test case uses the unary plus operator (`+`) to convert the number 500 to a string and then pushes it to the array `nums`.
4. **`"ES6"`**: This test case uses template literals (introduced in ECMAScript 2015) to create a string from the number 500 and pushes it to the array `nums`.

**Comparison of Options**

Let's analyze each option:

* **`String()` vs `.toString()`**: Both methods convert a value to its string representation. The main difference is that `.toString()` is a method call, while `String()` is a function invocation (more on this later). In terms of performance, both are usually equivalent.
* **`+` vs `'' + num`**: Using the unary plus operator (`+`) versus concatenating an empty string (`''`) with the number using template literals. The `+` approach is generally faster because it avoids creating a temporary string object and instead uses a simple arithmetic operation.
* **ES6 (template literals)**: Template literals are a feature introduced in ECMAScript 2015, which allows you to embed expressions inside string literals using backticks (`). This syntax can make code more readable, but performance-wise, it's usually comparable to the `+` approach.

**Library and Special JS Features**

* **`String()` vs `.toString()`**: These two methods are built-in JavaScript functions. `.toString()` is a method call, while `String()` is a function invocation.
* **ES6 (template literals)**: Template literals are a standard feature in modern JavaScript engines. They're not specific to any library.

**Other Considerations**

When comparing these options, keep in mind that the performance difference might be negligible for most use cases. However, if you need to optimize string conversion in a critical path of your code, understanding these differences can help you make informed decisions.

**Alternatives**

If you're looking for alternatives, here are a few:

* For string concatenation, consider using the `Array.prototype.join()` method or a library like Lodash, which provides efficient string joining functions.
* If you need to convert numbers to strings frequently, you might want to consider pre-converting your number data type to strings (e.g., by adding a `toString()` method on your object) or using a different data structure that inherently supports string representation.

I hope this explanation helps you understand the world of JavaScript microbenchmarks and provides valuable insights into optimizing string conversion in your code!

Related benchmarks:

String() vs .toString() vs + vs ES6 (version: 1)

Comparing performance of: String() vs .toString() vs Plus string vs String plus vs ES6

Created: 3 years ago by: Registered User

Jump to the latest result

String()

.toString()

Plus string

String plus

ES6

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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