This benchmark explores the performance differences between various methods of selecting functions in JavaScript based on a specific input "level." The primary methods being compared are:

1. if-else statements (getFnIf)
2. switch statements (getFnSwitch)
3. lookup through an object using string keys (getFnLookupString)
4. lookup through an object using numerical keys (getFnLookupN)
5. lookup through an array (getFnLookupA)

Method Comparisons

1. If-Else Statements (getFnIf):

   • Pros:
     • Straightforward syntax, easy to read.
     • Can handle complex conditional logic beyond simple equality.
   • Cons:
     • Each condition needs to be evaluated in the order given; as the number of conditions grows, performance may degrade.
     • Does not scale well for a large number of conditions, making it less efficient.

2. Switch Statements (getFnSwitch):

   • Pros:
     • More readable when multiple branches are involved; better suited for discrete values.
     • Compilers may handle them more efficiently than multiple if-else statements in some cases.
   • Cons:
     • Still evaluates conditions in sequence for the first matching case.
     • Less flexible compared to if-else statements for complex conditions.

3. Lookup Object with Strings (getFnLookupString):

   • Pros:
     • Very efficient for direct retrieval; no condition evaluation occurs once the object is created.
     • Easy to read and maintain as mappings are centralized.
   • Cons:
     • Requires additional memory overhead to store the lookup table.
     • Inefficient for a large number of unique keys that share similar prefixes.

4. Lookup Object with Numbers (getFnLookupN):

   • Pros:
     • Similar advantages to the string lookup but specifically optimized for number-based keys.
     • Very efficient in terms of lookup time.
   • Cons:
     • Like string mappings, it can incur memory overhead.
     • Limited to integer keys, which might not fit all use cases.

5. Lookup in Array (getFnLookupA):

   • Pros:
     • Fast access, especially when the index is static or predictable.
     • Memory-efficient if the number of elements is small and known.
   • Cons:
     • Index-based lookup can lead to unclear code if the mapping is not appropriately documented.
     • Requires numeric keys, which limits flexibility when the keys are not sequential.

Performance Results

Based on the results from the benchmark, the performance measured in executions per second showcased the following order of efficiency:

1. if: 146,164,656 executions/sec
2. switch: 145,137,392 executions/sec
3. lookup with strings: 71,823,064 executions/sec
4. lookup in array: 43,572,224 executions/sec
5. lookup with number: 41,335,268 executions/sec

Other Considerations

• Significant performance differences are apparent, especially between conditional statements (if and switch) and lookup approaches.
• The methods that utilize lookups (object-based and array-based) generally execute slower in this case but are more maintainable for larger applications with a significant number of potential conditions.
• The use of lookup tables can minimize the need for repeated evaluations, which is advantageous in performance-critical scenarios.

Alternatives

Other alternatives include:

• Function Maps with Closures: Using functions as first-class citizens may lead to a more functional programming approach.
• Using Maps: The Map object in JavaScript is better suited for dynamic key-value pairs and can provide better performance for size and key complexity.
• Control Flow Libraries: Libraries like Ramda or Lodash can help manage more complex conditions and function references efficiently.

This benchmark serves to inform developers about these decisions, providing insight into when it may be suitable to opt for one approach over the other based on performance needs and code maintainability.