Benchmark: typeof_vs_instanceof

Tests:

instanceof
const i = {} instanceof Object
typeof
const i = typeof {} === 'object'

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
instanceof
typeof

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Definition**
The benchmark definition is a JSON object that defines two test cases:

1. `typeof_vs_instanceof`: This test case checks if the `typeof` operator returns the string `'object'` for an empty object (`{}`).
2. Two individual test cases:
	* `instanceof`: This test case checks if an instance of the `Object` class is true.
	* `typeof`: This test case checks if the result of `typeof` applied to an empty object (`{}`) returns the string `'object'`.

**Options Compared**
Two options are compared in this benchmark:

1. **`typeof` operator**: Returns a string indicating the type of the operand, including 'object', 'number', 'string', etc.
2. **`instanceof` operator**: Returns true if the operand is an instance of the given constructor.

**Pros and Cons**

* `typeof` operator:
	+ Pros: Simple to use, does not require a specific class or constructor to test against.
	+ Cons: Does not provide information about the actual type (e.g., whether it's an object with some methods), only its category (e.g., 'object', 'number').
* `instanceof` operator:
	+ Pros: Provides more accurate results regarding the actual type and class hierarchy, allowing for deeper checks.
	+ Cons: Requires a specific class or constructor to test against, which can be brittle if not properly defined.

**Library/Functionality Used**
None of the test cases explicitly use a library. However, `typeof` is a built-in JavaScript operator, while `instanceof` is also part of the JavaScript language specification.

**Special JS Feature/Syntax (No mention in this benchmark)**
There is no special JavaScript feature or syntax mentioned in this benchmark.

**Other Alternatives**

For comparing types, other alternatives to `typeof` include:

* `Object.prototype.toString.call()` (a more verbose and less readable way to get the type)
* `String(type)` (returns a string representation of the value's type)

For checking class hierarchy, alternatives to `instanceof` include:

* Using a library like Lodash or Ramda for type checks
* Implementing custom checks using object methods and prototypes

In summary, this benchmark provides a basic comparison between two common JavaScript operators: `typeof` and `instanceof`. It highlights the pros and cons of each approach, which can be helpful for developers to choose the most suitable option depending on their specific use case.

Related benchmarks:

typeof_vs_instanceof (version: 0)

Comparing performance of: instanceof vs typeof

Created: 4 years ago by: Guest

Jump to the latest result

instanceof

typeof

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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