What is being tested on MeasureThat.net?

MeasureThat.net measures the performance of JavaScript microbenchmarks, specifically in the context of iterating over object properties using different methods.

Options compared:

Three options are compared:

1. For-in loop: The traditional for-in loop uses in keyword to iterate over an object's own property names.
2. Object.keys() method: The Object.keys() method returns an array of a given object's own property names, which can then be iterated using various methods such as forEach.
3. Array-like iteration with object keys: This approach uses the length of the object's keys property and iterates over it directly.

Pros and Cons:

1. For-in loop:
   • Pros: Simple and straightforward, well-suited for iterating over objects with non-enumerable properties.
   • Cons: Can be slower due to unnecessary iterations over non-existent properties.
2. Object.keys() method:
   • Pros: Efficient and modern approach, suitable for most use cases.
   • Cons: May be slower than the traditional for-in loop in some cases, as it involves creating an array of property names.
3. Array-like iteration with object keys:
   • Pros: Similar performance to the Object.keys() method, with the added benefit of direct access to property values.
   • Cons: Less readable and less common than using the Object.keys() method.

Library usage:

None of the benchmark definitions explicitly use any external libraries. However, the use of Object.keys() implies that the JavaScript engine being tested is able to provide an optimized implementation for this method.

Special JS features/syntax:

None of the benchmark definitions use any special or advanced JavaScript features such as ES6 syntax, async/await, or Web Workers. The code uses standard ECMAScript 5 syntax and should be compatible with most modern browsers.

Other alternatives:

If you want to test other iteration methods, MeasureThat.net provides a few options:

• Using for...in with the hasOwnProperty() method to filter out non-enumerable properties.
• Iterating over object property names using the Object.getOwnPropertyNames() method (not available in all browsers).
• Using the Map data structure instead of objects for iteration.

You can add these alternatives by modifying the benchmark definitions and providing new test cases. Keep in mind that each alternative may have different performance characteristics, so it's essential to test them thoroughly.