Benchmark: Testing123 - MeasureThat.net

Script Preparation code:

var data = 'string'

Tests:

Object.prototype.toString.call
Object.prototype.toString.call(data).slice(8, -1).toLowerCase() === 'string'
typeof
typeof data === 'string'

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.prototype.toString.call
typeof

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36

Browser/OS: Chrome 95 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Object.prototype.toString.call	4284793.5 Ops/sec
typeof	14519345.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what is being tested, compared, and analyzed.

**Benchmark Overview**

The benchmark measures the performance of two different approaches to check if a variable is a string:

1. `typeof data === 'string'`
2. `Object.prototype.toString.call(data).slice(8, -1).toLowerCase() === 'string'`

**Comparison of Approaches**

There are two main approaches being compared:

### 1. `typeof data === 'string'`

This approach uses the `typeof` operator to check the type of the variable `data`. The `typeof` operator returns a string indicating the type of the value, such as `'string'`, `'number'`, etc.

**Pros:**

* Simple and straightforward
* Fast, as it only involves a single operation

**Cons:**

* May not work correctly for certain types of strings (e.g., internationalized strings)
* May be affected by the engine's type inference rules

### 2. `Object.prototype.toString.call(data).slice(8, -1).toLowerCase() === 'string'`

This approach uses a more complex method to check if `data` is a string:

1. `Object.prototype.toString.call(data)` calls the `toString()` method on the object `data`, which returns a string representation of the object.
2. `.slice(8, -1)` extracts a substring from the result, starting at index 8 and ending at the second-to-last character.
3. `.toLowerCase()` converts the resulting string to lowercase.
4. The final comparison `=== 'string'` checks if the extracted substring matches the expected string `'string'`.

**Pros:**

* Works correctly for all types of strings
* Avoids potential issues with type inference rules

**Cons:**

* More complex and slower than the simple `typeof` approach
* May be less efficient due to the additional operations involved

**Library/Function Usage**

In this benchmark, the following functions/libraries are used:

* `Object.prototype.toString.call()`: a method call on the built-in `Object.prototype` object.
* `String.prototype.toLowerCase()` and `String.prototype.slice()`: methods on the built-in `String` prototype.

These functions are part of the JavaScript standard library and are implemented by the engine.

**Special JS Feature/Syntax**

There is no special JavaScript feature or syntax being used in this benchmark. The focus is solely on comparing two simple string checking approaches.

**Other Alternatives**

If you were to rewrite a similar benchmark, you might consider using alternative approaches, such as:

* Using a library like `assert` to check if the variable is a string
* Implementing a custom string checking function that takes into account specific requirements or edge cases
* Using a more modern JavaScript feature, such as template literals or `String.prototype.startsWith()`, to simplify the string checking logic.

Related benchmarks:

Testing123 (version: 0)

testing123

Comparing performance of: Object.prototype.toString.call vs typeof

Created: 3 years ago by: Guest

Jump to the latest result

Object.prototype.toString.call

typeof

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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