Let's break down the provided benchmark definition and test cases to understand what is being tested.

What is being tested?

MeasureThat.net is testing the performance of different approaches when setting values in a Map object using JavaScript. Specifically, it's checking how fast these operations are executed on various browsers.

The test creates a new Map object called map1, sets two key-value pairs with different values (null and undefined), deletes those keys, and then measures the execution time of each operation.

Options compared

Three options are being compared:

1. Setting a null value: The first test case sets both a and b to null.
2. Setting an undefined value: The second test case sets both a and b to undefined.
3. Deleting key-value pairs: The third test case deletes the existing key-value pairs using map1.delete('a'); and map1.delete('b');.

Pros and cons of each approach

• Setting a null value: This is a straightforward operation that simply sets the specified key to null. However, it may not be optimized by the JavaScript engine in some browsers.
  • Pros: Simple, well-supported by most browsers.
  • Cons: May not be as efficient as other approaches.
• Setting an undefined value: Similar to setting a null value, but using the undefined keyword instead. This approach is also straightforward and widely supported.
  • Pros: Similar to setting a null value, with similar pros and cons.
  • Cons: Same as above.
• Deleting key-value pairs: This operation may be less efficient than setting values because it involves searching for the key in the map and removing it if found. However, modern JavaScript engines often optimize this process.
  • Pros: May be more efficient than setting a value due to optimization by the engine.
  • Cons: Can be slower if not optimized properly.

Library used

The Map object is a built-in JavaScript object that uses a hash table data structure to store key-value pairs. It's widely supported across modern browsers and environments.

Special JS features or syntax (None)

There are no special JavaScript features or syntaxes being tested in this benchmark.

Other alternatives

If MeasureThat.net were to add more test cases, it might consider testing other approaches, such as:

• Using the Map.set(null, null) method instead of simply setting a key to null.
• Using the Map.set(undefined, undefined) method instead of simply setting a key to undefined.
• Implementing custom hash table or map implementations using native code (e.g., C++).
• Testing different data types as values in the map (e.g., numbers, strings, objects).

Keep in mind that these alternative approaches would likely be less common and may not offer significant performance benefits.