Benchmark: Number vs + vs parseFloat vs Math.Round (round to 2 decimal places)

Tests:

Number
const number = Number(Math.random().toFixed(2));
Unary +
const unary = +Math.random().toFixed(2);
parseFloat
const parse = parseFloat(Math.random().toFixed(2));
multiply, math round, divide
const multiply = Math.round(Math.random() * 100) / 100

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Number
Unary +
parseFloat
multiply, math round, divide

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 131 on Android

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Test name	Executions per second
Number	1005265.9 Ops/sec
Unary +	1288601.4 Ops/sec
parseFloat	1002246.8 Ops/sec
multiply, math round, divide	2071935.8 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):

LLMs can make mistakes. Check important info.

The benchmark provided is aimed at comparing four different methods for rounding a generated random number to two decimal places in JavaScript. Each method leverages a different approach to conversion and mathematical transformation. Here's a breakdown of each test case, the libraries (if any), and pros and cons associated with the options.

### Test Cases and Comparison

1. **Number**
   - **Test Name**: Number
   - **Benchmark Definition**: `const number = Number(Math.random().toFixed(2));`
   - **Description**: The `toFixed` method formats a number using fixed-point notation (e.g., rounding to two decimal places) and returns it as a string. The `Number` constructor then converts this string back into a number.
   - **Pros**: Straightforward and clearly expresses intent.
   - **Cons**: Potentially less efficient due to the intermediate string conversion.

2. **Unary +**
   - **Test Name**: Unary +
   - **Benchmark Definition**: `const unary = +Math.random().toFixed(2);`
   - **Description**: Similar to the `Number` method but uses the unary plus operator to convert the string returned by `toFixed` back into a number.
   - **Pros**: More concise and slightly performance-optimized compared to `Number` for cases where the unary operator is faster.
   - **Cons**: May be less readable for less experienced developers who are unfamiliar with the unary operator's behavior.

3. **parseFloat**
   - **Test Name**: parseFloat
   - **Benchmark Definition**: `const parse = parseFloat(Math.random().toFixed(2));`
   - **Description**: This approach also uses `toFixed` for rounding and returns a string, which is then parsed back into a floating-point number using `parseFloat`.
   - **Pros**: Similar to the first method but more explicit in that it indicates the intent to parse a string as a floating-point number.
   - **Cons**: Like the `Number` method, it may be less efficient due to string parsing overhead.

4. **Multiply, Math.round, Divide**
   - **Test Name**: multiply, math round, divide
   - **Benchmark Definition**: `const multiply = Math.round(Math.random() * 100) / 100`
   - **Description**: This method generates a random number, multiplies it by 100, rounds it to the nearest integer using `Math.round`, and then divides by 100 to scale it back to the original range.
   - **Pros**: Directly constructs the rounded number without converting between types, which can yield better performance.
   - **Cons**: Depending on the context, it may be less intuitive to developers unfamiliar with rounding strategies in JavaScript.

### Benchmark Results

From the benchmark results, the method that performed best was:
- **Multiply, Math Round, Divide**: 7,021,517 executions per second
- **Unary +**: 5,978,571 executions per second
- **Number**: 4,348,877 executions per second
- **parseFloat**: 4,256,937 executions per second

### Considerations

- **Performance**: The `multiply, math round, divide` approach is the most efficient for this specific operation. In applications where performance is critical, choosing a method that minimizes type conversion and utilizes native Math functions optimally can reduce execution time.
  
- **Readability**: While performance is valuable, code maintainability and readability should also be considered. For teams or projects where readability is prioritized, the `Number` and `parseFloat` methods might be more appropriate, especially for engineers less familiar with the nuances of JavaScript's type conversion.

### Alternatives

While the methods mentioned above are common, other alternatives for rounding numbers could include:
- **Using Intl.NumberFormat**: This built-in object can format numbers as strings in a locale-sensitive manner, including rounding, but it's not typically used for performance-sensitive calculations.
- **Custom rounding functions**: Developers could implement their own rounding logic to cater to specific requirements or scenarios where the built-in functions are not sufficient.

### Conclusion

The benchmark provides insight into the performance considerations when executing simple arithmetic operations, highlighting that different methods yield varying efficiency and readability. Choosing the right approach should consider both the performance needs of the application and the team's familiarity with the JavaScript language features.

Related benchmarks:

Number vs + vs parseFloat vs Math.Round (round to 2 decimal places) (version: 1)

Comparing performance of: Number vs Unary + vs parseFloat vs multiply, math round, divide

Created: one month ago by: Guest

Jump to the latest result

Number

Unary +

parseFloat

multiply, math round, divide

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):