Benchmark: if undefined comparison

Tests:

case 1
const obj = { 2: true, 7: true } if (obj[3]) { } obj[3] = true;
case 2
const obj = { 2: true, 7: true } if (typeof obj[3] !== 'undefined') { } obj[3] = true;
case 3
const obj = { 2: true, 7: true } if (obj[3] !== undefined) { } obj[3] = true;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
case 1
case 2
case 3

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
case 1	1009767680.0 Ops/sec
case 2	1018253568.0 Ops/sec
case 3	18096204.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition JSON**

The provided benchmark definition JSON represents a simple test case that compares three different approaches to check if a specific property exists in an object:

* `if (obj[3])`
* `if (typeof obj[3] !== 'undefined')`
* `if (obj[3] !== undefined)`

These three options are used to check if the property `3` exists in the object `obj`. The properties of these options are as follows:

* **Option 1: `if (obj[3])`**
	+ This option uses bracket notation (`obj[3]`) to access the property. If the property does not exist, it returns `undefined`.
	+ Pros:
		- Simple and concise
	+ Cons:
		- May be slower due to the lookup operation
* **Option 2: `if (typeof obj[3] !== 'undefined')`**
	+ This option uses the `typeof` operator to check if the property is an object or a primitive value. If it's not, it returns `true`.
	+ Pros:
		- More accurate than bracket notation alone
	+ Cons:
		- May be slower due to the additional lookup operation and type checking
* **Option 3: `if (obj[3] !== undefined)`**
	+ This option uses a simple comparison operator (`!==`) to check if the property is an object or a primitive value. If it's not, it returns `true`.
	+ Pros:
		- Similar performance to Option 2
	+ Cons:
		- May be less accurate than Option 2 due to type coercion

**Library and Special JS Features**

None of the test cases use any libraries or special JavaScript features beyond standard ECMAScript syntax.

**Benchmark Preparation Code**

The benchmark preparation code is empty, which means that no additional setup or initialization is required before running the benchmark.

**Latest Benchmark Result**

The latest benchmark result shows three different execution counts for each test case:

* **Test Case 1: `if (obj[3])`**
	+ Executions per second: 1018253568.0
* **Test Case 2: `if (typeof obj[3] !== 'undefined')`**
	+ Executions per second: 1009767680.0
* **Test Case 3: `if (obj[3] !== undefined)`**
	+ Executions per second: 18096204.0

**Other Alternatives**

If you're interested in exploring alternative approaches, here are a few options:

* Use the `in` operator instead of bracket notation: `if ('3' in obj)`
* Use a custom function to check if a property exists: `function hasProperty(obj, prop) { return Object.prototype.hasOwnProperty.call(obj, prop); }`
* Use a library like Lodash or Ramda to provide a more concise and expressive way to check for property existence.

Keep in mind that these alternatives may have different performance characteristics or trade-offs in terms of readability and maintainability.

Related benchmarks:

if undefined comparison (version: 0)

Comparing performance of: case 1 vs case 2 vs case 3

Created: one year ago by: Guest

Jump to the latest result

case 1

case 2

case 3

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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