Benchmark: String() vs .toString() vs concat

Script Preparation code:

var num = 500;

Tests:

String()
String(num)
.toString()
num.toString()
concat
''+num
template
`${num}`

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
String()
.toString()
concat
template

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/129.0.0.0 Safari/537.36

Browser/OS: Chrome 129 on Windows

View result in a separate tab

Test name	Executions per second
String()	5732009.5 Ops/sec
.toString()	14411454.0 Ops/sec
concat	14943605.0 Ops/sec
template	15157106.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 2 months ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON compares different methods of converting a number into a string in JavaScript. Specifically, it evaluates four different approaches:

1. **String(num)** - This method uses the `String` constructor to convert the numeric value to a string.
2. **num.toString()** - This calls the `toString()` method on the number, which is an inherent method of number objects in JavaScript that converts the number to its string representation.
3. **'' + num** - This method concatenates an empty string (`''`) with the number, leveraging JavaScript's type coercion. The empty string prompts the number to be converted to a string.
4. **`${num}`** - This uses template literals (backticks ``) to perform string interpolation, which allows embedding expressions within string literals.

### Pros and Cons of Each Approach:

1. **String(num)**:
   - **Pros**: Clear and straightforward, likely the most readable for someone unfamiliar with JavaScript. It clearly indicates the intent of converting a number to a string.
   - **Cons**: It is generally slower than the other methods in terms of execution time. This performance penalty becomes significant in scenarios that involve large numbers of conversions.

2. **num.toString()**:
   - **Pros**: More direct approach since it's a method that specifically converts a number to a string. It is usually faster than using the `String()` constructor.
   - **Cons**: It can only be called on numeric values. If the variable is potentially undefined or null, it may throw an error.

3. **'' + num (Concatenation)**:
   - **Pros**: This method takes advantage of JavaScript's type coercion, which can make it quite efficient. It is often one of the fastest methods for converting numbers to strings. 
   - **Cons**: Might be less readable for individuals unfamiliar with JavaScript's coercion rules, as it relies on implicit behavior of the language.

4. **`${num}` (Template Literals)**:
   - **Pros**: Very readable and can easily accommodate complex expressions. It also supports multi-line strings and string interpolation.
   - **Cons**: While generally fast, it may introduce a slight overhead due to the extra syntax compared to simple concatenation.

### Benchmark Results Summary:
The latest benchmark results indicate that in this particular execution environment (Chrome 129 on Windows), the performance of each method was as follows:

- **Template Literals**: 15,157,106 executions per second (fastest)
- **Concatenation**: 14,943,605 executions per second (second fastest)
- **toString() Method**: 14,411,454 executions per second
- **String() Constructor**: 5,732,009 executions per second (slowest)

### Other Considerations:
- **Performance**: If performance is critical, developers may want to avoid the `String()` constructor due to its lower execution speed compared to the other options.
- **Readability**: For clearer intent in the source code, many developers may prefer `toString()` or template literals despite slight performance differences.
- **Context Matters**: The choice of method might also depend on the context of its use, such as whether the variable might be undefined/null, how the code will be maintained, or if there's a need for complex string formatting.

### Alternatives:
Other alternatives for converting numbers to strings in JavaScript can include:
- **Number.prototype.toLocaleString()**: Converts a number into a local string format, accounting for locale-specific details (like thousands separators).
- **`String(num)` with additional options**: While `String()` is slower, it can accept more complex data types (like arrays or objects) and convert them to strings, making it versatile in certain contexts.

In summary, the benchmark effectively highlights the performance differences between common idioms for numeric to string conversion in JavaScript, providing insights that can guide developers based on their specific needs for performance and readability.

Related benchmarks:

String() vs .toString() vs concat (version: 3)

Comparing performance of: String() vs .toString() vs concat vs template

Created: 2 months ago by: Registered User

Jump to the latest result

String()

.toString()

concat

template

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 2 months ago):