Salesforce JavaScript Developer Practice Exam

Which type of loop should be used to iterate over elements directly in an array?

1. for ... of

2. for ... in

3. forEach

4. map

The correct answer is: for ... of

Using the "for ... of" loop is the most suitable choice for directly iterating over elements in an array because it provides a straightforward syntax and grants easy access to each individual element. This loop allows you to iterate over iterable objects, including arrays, without needing to access the index or use additional functions. Each iteration of the loop directly provides the value of the element, enhancing both readability and performance for simple use cases. The "forEach" method is indeed a viable option for iterating over arrays but is a higher-order function that doesn't allow for early termination of the loop, making it less flexible than the "for ... of" structure. Similarly, the "map" method is designed for transforming an array and returning a new array, which adds unnecessary overhead if the goal is simply to iterate through the elements. The "for ... in" loop, while it can be used to iterate over object properties, is generally not recommended for arrays since it iterates over all enumerable properties and not just the array elements, which can lead to unexpected results when dealing with inherited properties or additional object properties.