Benchmark: Option chaining and typeof

Script Preparation code:

window._x = { y: 4 };
window._z = null;

Tests:

Optional chaining, not null
let a = typeof _x?.y === `number`;
Explicit null check, not null
let a = _x != null && typeof _x.y === `number`;
Optional chaining, null
let a = typeof _z?.y === `number`;
Explicit null check, null
let a = _z != null && typeof _z.y === `number`;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Optional chaining, not null
Explicit null check, not null
Optional chaining, null
Explicit null check, null

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark compares two approaches to check if a value is an object with a specific property:

1. Optional chaining (`?.`)
2. Explicit null check (`!= null`)

**Optional Chaining (`?.`)**

Optional chaining allows you to access nested properties of an object without throwing an error if the property doesn't exist. In this benchmark, optional chaining is used to check if `_x.y` exists and is a number.

The JavaScript syntax `typeof _x?.y === "number"` uses optional chaining to safely access the `y` property of the `_x` object. If `_x` is null or undefined, the expression will return `null`, not throw an error.

**Explicit Null Check (`!= null`)**

An explicit null check uses the `!= null` operator to verify that a value is not null or undefined before accessing its properties. In this benchmark, this approach is used in two variations:

* "Optional chaining, not null"
* "Explicit null check, not null"

**Other Considerations**

Both approaches have pros and cons:

Pros of Optional Chaining (`?.`):

* More concise syntax
* Avoids errors when dealing with null or undefined values

Cons of Optional Chaining (`?.`):

* May be less readable for developers who are not familiar with the syntax
* Can lead to unexpected behavior if not used carefully (e.g., using `?.` on a primitive value)

Pros of Explicit Null Check (`!= null`):

* More readable and understandable by most developers
* Allows for explicit control over error handling

Cons of Explicit Null Check (`!= null`):

* Requires more code to achieve the same result as optional chaining
* Can lead to boilerplate code if not used carefully (e.g., multiple `!= null` checks)

**Library and Special JS Features**

There is no library being tested in this benchmark. However, it's worth noting that JavaScript features like optional chaining (`?.`) are part of the ECMAScript standard and have been supported by most modern browsers since their introduction.

No special JavaScript syntax or features are used in this benchmark.

**Alternatives**

Other alternatives to these two approaches include:

* Using a more explicit null check with a separate variable, e.g., `const isObject = _x !== null && typeof _x.y === "number";`
* Using a library like Lodash, which provides a function called `isPlainObject()` that can be used for similar checks.

However, for this specific benchmark, the focus is on comparing the performance of optional chaining (`?.`) and explicit null checks (`!= null`), making these alternatives less relevant.

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/114.0.0.0 Safari/537.36

Browser/OS: Chrome 114 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Optional chaining, not null	17097368.0 Ops/sec
Explicit null check, not null	8556481.0 Ops/sec
Optional chaining, null	16938890.0 Ops/sec
Explicit null check, null	16811774.0 Ops/sec

Related benchmarks:

Option chaining and typeof (version: 0)

Comparing performance of: Optional chaining, not null vs Explicit null check, not null vs Optional chaining, null vs Explicit null check, null

Created: one year ago by: Guest

Jump to the latest result

Optional chaining, not null

Explicit null check, not null

Optional chaining, null

Explicit null check, null

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):