Benchmark: switch on object references

Script Preparation code:

var AAA = {key: "AAA", idx: 0};
var BBB = {key: "BBB", idx: 1};
var CCC = {key: "CCC", idx: 2};
var DDD = {key: "DDD", idx: 3};
var EEE = {key: "EEE", idx: 4};
var arr = [AAA, BBB, CCC, DDD, EEE];
for (let i = 5; i < 1000; i++) {
  arr[i] = arr[i % 5];
}

Tests:

switch on string
var sum = 0; for (let i = 0; i < arr.length; i++) { switch (arr[i].key) { case "AAA": sum += 1; break; case "BBB": sum += 2; break; case "CCC": sum += 3; break; case "DDD": sum += 4; break; case "EEE": sum += 5; break; } }
switch on object
var sum = 0; for (let i = 0; i < arr.length; i++) { switch (arr[i]) { case AAA: sum += 1; break; case BBB: sum += 2; break; case CCC: sum += 3; break; case DDD: sum += 4; break; case EEE: sum += 5; break; } }
switch on number
var sum = 0; for (let i = 0; i < arr.length; i++) { switch (arr[i].idx % 5 | 0) { case 0: sum += 1; break; case 1: sum += 2; break; case 2: sum += 3; break; case 3: sum += 4; break; case 4: sum += 5; break; } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
switch on string
switch on object
switch on number

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 27 days ago):

LLMs can make mistakes. Check important info.

The benchmark defined at MeasureThat.net assesses the performance of different `switch` statement implementations in JavaScript when handling various types of data. Specifically, three test cases are compared:

### Test Cases:

1. **Switch on String**:
   - **Code**: The benchmark iterates over an array of objects (`arr`) and uses the `.key` property of each object in a `switch` statement.
   - **Pros**: String comparisons (`case "AAA":`, etc.) are clear and straightforward to implement, making the code easy to read and maintain. The `key` property provides meaningful identifiers.
   - **Cons**: String comparison may be less efficient due to the need to compare the content of strings, which can be more resource-intensive than checking references.

2. **Switch on Object**:
   - **Code**: This benchmark uses direct object references (`AAA`, `BBB`, etc.) in the `switch` statement.
   - **Pros**: Identity comparison is performed here, which is likely the fastest way of evaluating the cases because objects are compared by reference, not by value. Thus, there's no need to convert or evaluate properties for comparison.
   - **Cons**: While the performance is better, this approach can be less flexible and less readable than using strings. If the objects were to change or were generated dynamically, the structure would be less understandable, especially for those unfamiliar with the codebase.

3. **Switch on Number**:
   - **Code**: Here, the benchmark evaluates the `idx` property (interpreted as an integer) using a numeric case switch based on the modulus of 5.
   - **Pros**: Numeric comparisons are typically faster than string comparisons and also faster than object reference comparisons in this case, especially when using simple arithmetic and bitwise operations (e.g., `| 0` for flooring).
   - **Cons**: The readability might be slightly sacrificed compared to switches by string, as the significance of `idx` might not be immediately clear to someone reading the code without context.

### Libraries and JavaScript Features:
No specific libraries are utilized in these benchmarks; the benchmarks rely solely on core JavaScript constructs. The `switch` statement is a part of the JavaScript language specification and does not require any external libraries to utilize.

### Performance Results:
The benchmark results indicate the number of executions per second for each test case when run in a specific environment (Chrome 129 on Mac OS X 10.15.7):
- **Switch on String**: 16,653.91 executions/sec
- **Switch on Number**: 16,264.24 executions/sec
- **Switch on Object**: 6,268.69 executions/sec

### Considerations:
- **Maintainability vs. Performance**: While object reference comparisons may offer better performance, they can be less maintainable due to potentially confusing code structures when using raw objects. Code should be written with a consideration of the likelihood of changes over time.
- **Context of Use**: The choice between using strings, numbers, or objects can depend on the ultimate context of the application. If performance is paramount in a section of code that's called frequently, then object references might be preferred. In contrast, if maintainability is a priority, leveraging strings can lead to clearer code.

### Alternatives:
- **If Performance is Critical**: Consider using data structures better suited for high-performance lookups, such as `Map` or even implementing a hash table if the data permits.
- **If Readability Matters**: Alternatives like `if-else` statements may also be employed, although they might have different performance characteristics based on the type of data and the number of conditions.
- **Functional Approaches**: For more modern JavaScript, employing functions or even function maps can sometimes produce clearer and more maintainable code especially in large codebases.

Overall, this benchmark provides insights into how different approaches can be evaluated and utilized in JavaScript while balancing performance and maintainability.

Latest run results:

Run details: (Test run date: 27 days ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:131.0) Gecko/20100101 Firefox/131.0

Browser/OS: Firefox 131 on Linux

View result in a separate tab

Test name	Executions per second
switch on string	335853.3 Ops/sec
switch on object	745754.7 Ops/sec
switch on number	519284.7 Ops/sec

Related benchmarks:

switch on object references (version: 2)

Comparing performance of: switch on string vs switch on object vs switch on number

Created: 28 days ago by: Registered User

Jump to the latest result

switch on string

switch on object

switch on number

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 27 days ago):