Benchmark: Switch vs. dictionary

Script Preparation code:

var random = Math.floor(Math.random() * 20);

Tests:

Switch
switch (random) { case 0: random = -Math.PI; break; case 1: random = Math.EPSILON; break; case 2: case 3: case 4: case 5: case 6: case 7: case 8: case 9: random = 1; break; case 10: case 11: case 12: random /= 5; break; case 13: case 14: case 15: case 16: case 17: random **= 2; break; case 18: random = 5; break; case 19: random = 28; break; case 20: random = 0; break; default: random = -1; break; }
If
const test = { 0: () => -Math.PI, 1: () => Math.EPSILON, 2: () => 1, 3: () => 1, 4: () => 1, 5: () => 1, 6: () => 1, 7: () => 1, 8: () => 1, 9: () => 1, 10: (rand) => rand / 5, 11: (rand) => rand / 5, 12: (rand) => rand / 5, 13: (rand) => rand ** 2, 14: (rand) => rand ** 2, 15: (rand) => rand ** 2, 16: (rand) => rand ** 2, 17: (rand) => rand ** 2, 18: () => 5, 19: () => 28, 20: () => 0, }; random = test[random]?.() || -1;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Switch
If

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36 Edg/144.0.0.0

Browser/OS: Chrome 144 on Windows

View result in a separate tab

Test name	Executions per second
Switch	14325222.0 Ops/sec
If	7229917.0 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 explanation.

**Benchmark Definition**

The provided JSON represents a JavaScript benchmark that compares the performance of two approaches: `switch` statements and dictionary lookups (using the `const test` object).

**Options Compared**

There are two options being compared:

1. **Switch statement**: A traditional `switch` statement with multiple cases.
2. **Dictionary lookup**: Using an object (`test`) to map values to functions.

**Pros and Cons of Each Approach**

* **Switch Statement**
	+ Pros: Easy to read, understand, and maintain. Can be useful for complex conditional logic.
	+ Cons: Can lead to slower performance due to the overhead of jumping between cases using the instruction pointer. Modern JavaScript engines have optimized switch statements, but older ones may not perform as well.
* **Dictionary Lookup**
	+ Pros: Fast lookups with an average time complexity of O(1). Can be useful for simple conditional logic or when working with large datasets.
	+ Cons: May require more code to set up the dictionary, and can be less readable than switch statements.

**Other Considerations**

When choosing between a `switch` statement and a dictionary lookup, consider the following:

* Complexity of the conditional logic: For simple cases, a dictionary lookup may be faster. For complex cases, a `switch` statement might be more readable.
* Data size and frequency: If you're working with large datasets or need to look up values frequently, a dictionary lookup might be a better choice.

**Library**

In this benchmark, the `Math.EPSILON` constant is used, which is part of the JavaScript Math library. This constant represents a small positive value that can be added to 1 without affecting its equality.

**Special JS Features or Syntax**

None are explicitly mentioned in the provided code snippets. However, it's worth noting that modern JavaScript engines may use features like `const` and `let` for variable declarations, which can affect performance.

**Other Alternatives**

If you're interested in exploring alternative approaches, consider:

* **Object destructuring**: Instead of using a dictionary lookup, you could use object destructuring to extract values from an object.
* **Function composition**: You could create functions that take the value as input and return the corresponding result, allowing for more flexibility in your implementation.

Keep in mind that these alternatives might not provide a significant performance boost compared to the original `switch` statement and dictionary lookup approaches.

Related benchmarks:

Switch vs. dictionary (version: 0)

Comparing performance of: Switch vs If

Created: 4 years ago by: Guest

Jump to the latest result

Switch

If

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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