Benchmark: typeof vs instanceof vs constructor

Script Preparation code:

function Ticket(id) {
  this._id = id;
}

var testTicket = new Ticket(1);
var count = 1000;

​x
 
function Ticket(id) {  this._id = id;}​var testTicket = new Ticket(1);var count = 1000;

Tests:

typeof check

for (var i = 0; i < count; i += 1) {
  if (typeof testTicket === 'object') {
	continue;
  }
}

 
for (var i = 0; i < count; i += 1) {  if (typeof testTicket === 'object') {    continue;  }}

instanceof check

for (var i = 0; i < count; i += 1) {
  if (testTicket instanceof Ticket) {
	continue;
  }
}

 
for (var i = 0; i < count; i += 1) {  if (testTicket instanceof Ticket) {    continue;  }}

constructor check

for (var i = 0; i < count; i += 1) {
  if (testTicket.constructor.name === 'Ticket') {
	continue;
  }
}

 
for (var i = 0; i < count; i += 1) {  if (testTicket.constructor.name === 'Ticket') {    continue;  }}

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Experimental features:

Memory measurements supported only in Chrome.
For precise memory measurements Chrome must be launched with --enable-precise-memory-info flag.
More information: Monitoring JavaScript Memory

Test case name	Result
typeof check
instanceof check
constructor check

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser/OS: Chrome 135 on Windows

View result in a separate tab

Test name	Executions per second
typeof check	904218.9 Ops/sec
instanceof check	475233.9 Ops/sec
constructor check	78911.7 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

Overview

The provided JSON represents a JavaScript benchmark test case, where the user compares the performance of three different approaches: typeof, instanceof, and .constructor property.

Benchmark Purpose

The benchmark tests how fast each approach can identify whether an object is a subclass of another object (in this case, Ticket) or not. The purpose of this test is to understand which approach is the most efficient in terms of performance.

Options Compared

There are three options compared:

typeof: This checks if the object is a constructor function using the typeof operator.
instanceof: This checks if the object is an instance of another object (in this case, Ticket) using the instanceof operator.
.constructor.name === 'Ticket': This checks if the object's constructor has a property named name and its value is equal to 'Ticket'.

Pros and Cons of Each Approach

typeof:
- Pros: Simple and straightforward.
- Cons: May not work as expected for certain types (e.g., arrays, functions).
instanceof:
- Pros: More accurate than typeof for checking subclass relationships.
- Cons: Can be slower due to the overhead of the instanceof operator.
.constructor.name === 'Ticket':
- Pros: Fast and efficient.
- Cons: Requires access to the object's constructor property, which may not be available in all situations.

Library Used

The test case uses the Ticket class, which is a simple class definition provided by the benchmark author. The purpose of this class is to serve as a representative object for testing the instanceof operator.

Special JS Feature or Syntax

There is no special JavaScript feature or syntax used in this benchmark except for the use of the instanceof operator, which is a built-in operator in JavaScript.

Other Considerations

The test case uses a small sample size (1000 executions) to measure performance.
The benchmark runs on Firefox 131 and Windows desktop platforms.

Alternatives

If you wanted to compare these approaches using a different platform or browser, you could modify the RawUAString field in the benchmark result JSON to include additional information about the test environment. For example:

"RawUAString": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:131.0) Gecko/20100101 Firefox/131.0 Safari/537.36 Chrome/91.0.4472.124"

This would allow you to compare the performance of each approach on different platforms and browsers using MeasureThat.net.

LLMs can make mistakes. Check important info.

**Overview**

The provided JSON represents a JavaScript benchmark test case, where the user compares the performance of three different approaches: `typeof`, `instanceof`, and `.constructor` property.

**Benchmark Purpose**

The benchmark tests how fast each approach can identify whether an object is a subclass of another object (in this case, `Ticket`) or not. The purpose of this test is to understand which approach is the most efficient in terms of performance.

**Options Compared**

There are three options compared:

1. `typeof`: This checks if the object is a constructor function using the `typeof` operator.
2. `instanceof`: This checks if the object is an instance of another object (in this case, `Ticket`) using the `instanceof` operator.
3. `.constructor.name === 'Ticket'`: This checks if the object's constructor has a property named `name` and its value is equal to `'Ticket'`.

**Pros and Cons of Each Approach**

1. `typeof`:
	* Pros: Simple and straightforward.
	* Cons: May not work as expected for certain types (e.g., arrays, functions).
2. `instanceof`:
	* Pros: More accurate than `typeof` for checking subclass relationships.
	* Cons: Can be slower due to the overhead of the `instanceof` operator.
3. `.constructor.name === 'Ticket'`:
	* Pros: Fast and efficient.
	* Cons: Requires access to the object's constructor property, which may not be available in all situations.

**Library Used**

The test case uses the `Ticket` class, which is a simple class definition provided by the benchmark author. The purpose of this class is to serve as a representative object for testing the `instanceof` operator.

**Special JS Feature or Syntax**

There is no special JavaScript feature or syntax used in this benchmark except for the use of the `instanceof` operator, which is a built-in operator in JavaScript.

**Other Considerations**

* The test case uses a small sample size (1000 executions) to measure performance.
* The benchmark runs on Firefox 131 and Windows desktop platforms.

**Alternatives**

If you wanted to compare these approaches using a different platform or browser, you could modify the `RawUAString` field in the benchmark result JSON to include additional information about the test environment. For example:

```
"RawUAString": "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:131.0) Gecko/20100101 Firefox/131.0 Safari/537.36 Chrome/91.0.4472.124"
```

This would allow you to compare the performance of each approach on different platforms and browsers using MeasureThat.net.

Related benchmarks:

typeof vs instanceof vs constructor (version: 0)

Comparing typeof vs instanceof vs .constructor property

Comparing performance of: typeof check vs instanceof check vs constructor check

Created: 2 years ago by: Guest

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