Benchmark: switch case vs object

Tests:

switch case
const roleIndex = 0; let role; switch(roleIndex) { case 0: role = 'admin'; break; case 1: role = 'moderator'; break; default: role = 'user'; }
object
const roleIndex = 1; const role = { 0: 'admin', 1: 'moderator' }[roleIndex] ?? 'user';

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
switch case
object

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the provided JSON and explain what is being tested, compared, and considered in this JavaScript microbenchmark.

**Benchmark Definition**

The benchmark definition consists of two test cases:

1. `switch case`
2. `object`

Both test cases aim to measure the performance difference between using a traditional `switch` statement versus an object-based approach (using bracket notation).

**Switch Case Test Case**

In the `switch case` test case, we have:
```javascript
const roleIndex = 0;
let role;

switch(roleIndex) {
  case 0:
    role = 'admin';
    break;
  case 1:
    role = 'moderator';
    break;
  default:
    role = 'user';
}
```
This code uses a traditional `switch` statement to determine the value of `role` based on the input `roleIndex`.

**Object Test Case**

In the `object` test case, we have:
```javascript
const roleIndex = 1;

const role = {
  0: 'admin',
  1: 'moderator'
}[roleIndex] ?? 'user';
```
This code uses object-based bracket notation to achieve the same result as the traditional `switch` statement.

**Comparison**

The main difference between these two approaches is how they handle out-of-range values for `roleIndex`. In the `switch` case, there's no direct way to handle such values without using additional logic (e.g., a `default` branch). In contrast, the object-based approach provides a built-in way to handle unknown values with the nullish coalescing operator (`??`).

**Pros and Cons**

**Switch Case:**

Pros:

* Easier to read and understand for those familiar with traditional `switch` statements.
* Less code overall.

Cons:

* Requires an explicit `default` branch, which can add unnecessary complexity.
* Handles out-of-range values poorly without additional logic.

**Object Test Case:**

Pros:

* Provides a clean and concise way to handle unknown values.
* No need for additional logic or branches.

Cons:

* May be less intuitive for those unfamiliar with bracket notation.
* Requires understanding of the object's structure and key existence checks.

**Library/Function Considerations**

In this benchmark, there is no specific library used. However, it's worth noting that some JavaScript engines may provide optimizations or special handling for certain constructs (e.g., `switch` statements).

**Special JS Feature/Syntax**

The nullish coalescing operator (`??`) is a relatively recent feature in JavaScript (introduced in ECMAScript 2020). It provides a concise way to handle unknown values and avoid `undefined` issues.

In this benchmark, the object-based approach relies on this feature. If you're targeting older JavaScript engines that don't support `??`, you may need to use alternative approaches or polyfills.

**Alternatives**

If you wanted to test a different approach, some alternatives could be:

* Using `if-else` chains instead of traditional `switch` statements.
* Employing array-based lookups (e.g., `roleIndex in roles`) for object-based tests.
* Implementing custom solutions using `try-catch` blocks or other error-handling mechanisms.

Keep in mind that these alternatives would likely introduce more complexity and potentially different performance characteristics compared to the original switch-case and object-based approaches.

Related benchmarks:

switch case vs object (version: 0)

Comparing performance of: switch case vs object

Created: 2 years ago by: Guest

Jump to the latest result

switch case

object

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):