Benchmark: typeof vs sup - MeasureThat.net

Script Preparation code:

const s = "xxxxx";

Tests:

typeof
typeof s != "string"
sup
!s.sup

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof
sup

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36

Browser/OS: Chrome 140 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
typeof	182600336.0 Ops/sec
sup	190802128.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 months ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON is designed to compare the performance of two different methods for checking if a variable is a string in JavaScript. The two methods being tested are:

1. `typeof s != "string"`
2. `!s.sup`

### Test Cases Description

1. **Test Case: `typeof`**
   - **Benchmark Definition:** `typeof s != "string"`
   - This test checks whether the variable `s` is not of type `"string"` using the `typeof` operator. The `typeof` operator is a basic JavaScript mechanism that returns a string indicating the type of the unevaluated operand.
   
2. **Test Case: `sup`**
   - **Benchmark Definition:** `!s.sup`
   - This test checks if the string method `sup` (which is actually not a standard method for string objects) does not exist on the string variable `s`. If the method does not exist, `s.sup` would return `undefined`, and thus `!s.sup` would evaluate to `true`.

### Performance Results

The benchmark results indicate the number of executions per second for each test case, with the results being as follows:

- **`sup` Test:** 190,802,128 executions per second
- **`typeof` Test:** 182,600,336 executions per second

### Pros and Cons of Each Approach

- **`typeof` Approach**
  - **Pros:**
    - It is a well-established and standard way to check a variable's type.
    - The `typeof` operator is simple and easy to understand; it clearly indicates what type you are checking for.
  - **Cons:**
    - It might be slightly slower than simpler checks, especially for non-string types that evaluate to a falsy value.

- **`sup` Approach**
  - **Pros:**
    - The check utilizes property existence, which can be quite fast in scenarios where the method does not exist.
  - **Cons:**
    - The method `sup` is not standard and could lead to confusion. It’s not a commonly used or recommended practice to check the type of a variable. 
    - This approach relies on the presence of a specific method that may not generally be defined, which can lead to misleading results if other contexts are considered.
    - It does not provide information about the variable's type; it only signifies whether `s` has the `sup` method or not.

### Considerations and Alternatives

When measuring performance, it’s important to consider the broader context of what these checks are being used for. While both methods may yield valid results in terms of performance, the choice of which one to use should be guided by:

- **Clarity of Code:** Prioritize maintainability and clarity. Using `typeof` is generally clearer to other developers reading the code.
- **Context of Use:** If you are specifically working with string manipulations, understanding when specific properties or functions exist can be useful, but relying on non-standard checks can introduce risk.

#### Alternative Techniques:
- **Using `instanceof String`:** Another way to check if `s` is a string (if `s` is an instance of the String object) is `s instanceof String`. However, this method can sometimes yield unexpected results if primitive strings are used.
  
- **Checking with `s === ""`:** A simple check for an empty string can also provide some guarantees about the string type if that fits the use case.

### Conclusion

In this benchmark, comparing `typeof` string checking with a check against a non-standard string method illustrates the trade-offs between standard practices and alternative approaches that may yield different performance characteristics. Balancing efficiency with code clarity and maintainability is critical in making a decision on which method to employ in real-world applications.

Related benchmarks:

typeof vs sup (version: 1)

Comparing performance of: typeof vs sup

Created: 6 months ago by: Guest

Jump to the latest result

typeof

sup

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 6 months ago):