Benchmark: typeof vs truthyness benchmark

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

const test = "some-string";
let c = 0;

Tests:

typeof string
if (typeof test === 'string') { c++; }
truthyness
if (test) { c++; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof string
truthyness

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Linux

View result in a separate tab

Test name	Executions per second
typeof string	9740197.0 Ops/sec
truthyness	9745809.0 Ops/sec

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

LLMs can make mistakes. Check important info.

The benchmark you provided tests the performance of two different approaches for evaluating whether a variable is a string. Specifically, it compares the `typeof` operator and the truthiness check in JavaScript using a predefined string variable. Here’s a closer look at each method, along with potential pros and cons.

### Methods Compared

1. **`typeof` Operator**
   - **Test Case:** `if (typeof test === 'string') { c++; }`
   - **Purpose:** This condition checks explicitly if the variable `test` is of type "string".
   - **Pros:**
     - Clarity: Clearly expresses the intent of checking the variable's type.
     - Safety: Since it checks for the specific type, it avoids potential pitfalls associated with falsy values.
   - **Cons:**
     - Performance: The `typeof` operator may execute slightly slower in some contexts compared to simpler truthy evaluations, particularly when used in hot code paths.
     - Verbosity: Requires additional string comparison which may have a minor impact on performance.

2. **Truthiness Check**
   - **Test Case:** `if (test) { c++; }`
   - **Purpose:** This condition checks if `test` evaluates to a truthy value. In JavaScript, all non-empty strings are considered truthy, while `null`, `undefined`, `0`, an empty string `""`, and `NaN` are falsy.
   - **Pros:**
     - Performance: Might be faster in cases where type checking is unnecessary, since it only evaluates the truthiness of the variable.
     - Simplicity: Fewer characters of code may lead to more straightforward and concise expression.
   - **Cons:**
     - Ambiguity: This approach could lead to unintended behaviors if the variable might be falsy in other contexts, yielding safety vulnerabilities if the specific type is crucial.

### Benchmark Results Overview

The latest benchmark results show that both methods are highly performant, with the truthiness check slightly outperforming the `typeof` check:

- **Truthiness Check (`ExecutionsPerSecond`: 9,745,809.0)**
- **`typeof` Check (`ExecutionsPerSecond`: 9,740,197.0)**

Given the close proximity in performance, the choice between these methods may come down to context and specific requirements of the code being developed.

### Other Considerations

- **Use Cases:** In applications where you are strictly expecting a string and need type safety, the `typeof` operator is preferable. In contrast, if you are using this check in a situation where a variable may never contain a falsy value (like an always-initialized variable), then a truthiness check may be sufficient.
  
- **Readability:** Always consider the maintainability of code. Code readability is crucial in larger codebases, and having explicit type checks may make the code clearer for future developers.

### Alternatives

Other alternatives for type checking or determination could include:

- **`instanceof` Operator**: This checks if the variable is an instance of a particular type. However, it is more applicable to Object instances rather than primitive types like strings.
  
- **Using Wrapper Objects**: In some cases, using higher-level constructs might help, such as trying to coerce the variable into a string using `String(test)`; this does not serve as a direct comparison.

Each approach has its niche where it excels over others. The choice should be made based on the specific context, performance characteristics, and need for clarity versus conciseness in the code.

Related benchmarks:

typeof vs truthyness benchmark (version: 1)

Comparing performance of: typeof string vs truthyness

Created: one year ago by: Guest

Jump to the latest result

typeof string

truthyness

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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