Benchmark: Switch vs map - MeasureThat.net

Tests:

Switch
const input = 10; switch(input) { case 1: return true; case 2: return true; case 3: return true; case 4: return true; case 5: return true; case 6: return true; case 7: return true; case 8: return true; case 9: return true; case 10: return true; }
Map
const input = 10; const LUT = { 0: true, 1: true, 2: true, 3: true, 4: true, 5: true, 6: true, 7: true, 8: true, 9: true, 10: true } LUT[input];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Switch
Map

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Switch	214967552.0 Ops/sec
Map	223890144.0 Ops/sec

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

LLMs can make mistakes. Check important info.

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

The benchmark being tested is the comparison between two approaches: using a traditional `switch` statement and using an object lookup (also known as a hash table or associative array). The goal is to determine which approach is faster for this specific use case.

**Switch Statement**

The `switch` statement is used in the first test case. It takes an input value of 10 and checks if it matches any of the cases defined in the `switch` block. If a match is found, the corresponding code inside the `case` block is executed.

Here's what's happening under the hood:

1. The JavaScript engine parses the `switch` statement and generates a jump table (a data structure that maps values to indices) based on the input value.
2. When the input value is 10, the engine jumps directly to the corresponding `case` block.
3. Inside the `case` block, the code checks if the input value matches any of the cases using a simple equality check.

**Object Lookup (Map)**

The second test case uses an object lookup instead of a traditional `switch` statement. The same input value of 10 is used to access a hash table (`LUT`) that maps values to boolean results.

Here's what's happening under the hood:

1. The JavaScript engine creates a new hash table (`LUT`) that contains key-value pairs for the possible input values (0-10).
2. When the input value of 10 is used, the engine looks up the corresponding boolean result in the `LUT` using the input value as the key.
3. If a match is found, the resulting boolean value is returned.

**Comparison**

Now, let's talk about the pros and cons of each approach:

**Switch Statement:**

Pros:

* Simple to understand and implement
* Can be more readable for small codebases
* Uses less memory compared to an object lookup

Cons:

* Performance can degrade for large numbers of cases
* May not perform well with floating-point or complex comparisons
* Generates a jump table, which can increase memory usage

**Object Lookup (Map):**

Pros:

* Fast and efficient for lookups
* Can handle large numbers of cases without performance degradation
* Uses hash tables, which are optimized for fast lookups

Cons:

* More memory-intensive compared to switch statements
* Requires more complex code to implement
* May be less readable due to the need to define a hash table upfront.

**Other Considerations**

When using object lookup, it's essential to consider the following factors:

* Cache performance: If the `LUT` is large and contains many identical values, cache performance may improve.
* Memory usage: The size of the `LUT` will impact memory usage. Large hash tables can lead to increased memory allocation.

**Special JS Features**

There are no special JavaScript features or syntax mentioned in this benchmark. However, it's worth noting that some modern browsers support features like `const enum` for switch-like statements and optimized hash table lookups.

**Alternatives**

If you're looking for alternative approaches to this benchmark, consider the following:

* **Array-based approach:** Instead of using a hash table, use an array with index values corresponding to the input values. This can be faster than object lookup but may require more memory.
* **Binary search:** Use binary search algorithms to find the matching value in the `LUT`. This can be faster for large hash tables but may require more complex code.

In conclusion, this benchmark compares two approaches: traditional `switch` statements and object lookups (hash tables). The choice between these approaches depends on performance requirements, memory constraints, and readability considerations.

Related benchmarks:

Switch vs map (version: 0)

Comparing performance of: Switch vs Map

Created: 6 years ago by: Guest

Jump to the latest result

Switch

Map

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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