What are the differences between JavaScript's forEach() and for...of loops when iterating over arrays?
Gable E

1. Checking for an empty or whitespace-only string using regular expressions: To check if a value is an empty or whitespace-only string using regular expressions in JavaScript, you can utilize thetest() method of the regular expression object. Here's an example:

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function isEmptyOrWhitespace(value) {
  return /^\s*$/.test(value);
}

// Example usage
console.log(isEmptyOrWhitespace("")); // Output: true
console.log(isEmptyOrWhitespace("  ")); // Output: true
console.log(isEmptyOrWhitespace("  Hello  ")); // Output: false

In this example, theisEmptyOrWhitespace() function takes a stringvalue as input and uses the regular expression/^\s*$/ to test if the string is empty or consists of only whitespace characters. Thetest() method returnstrue if the string matches the regular expression, indicating that it is empty or whitespace-only. The regular expression/^\s*$/ consists of the following components: -^ asserts the start of the string. -\s* matches zero or more whitespace characters. -$ asserts the end of the string. By using this regular expression with thetest() method, you can effectively determine if a value is an empty or whitespace-only string. 2. Differences betweenforEach() andfor...of loops when iterating over arrays: BothforEach() andfor...of loops can be used to iterate over arrays in JavaScript, but they have some differences in terms of syntax and functionality: forEach(): - Syntax:array.forEach(callbackFunction(element, index, array)). - Executes a provided callback function once for each element in the array. - Callback function receives three arguments: the current element, its index, and the array being traversed. - The return value of the callback function is ignored. - Executes the callback function in the same order as the array elements. - Does not support breaking out of the loop (i.e., no equivalent ofbreak orcontinue statements). - Suitable for scenarios where you want to perform an operation on each element of the array. Example usage offorEach():

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const numbers = [1, 2, 3, 4];
numbers.forEach((number, index) => {
  console.log(`Element at index ${index}: ${number}`);
});

for...of: - Syntax:for (variable of array) { ... }. - Iterates over the values of an iterable object, including arrays. - Allows you to declare a new variable within the loop that represents the current element. - Executes the loop for each element in the array. - Supports breaking out of the loop usingbreak or skipping to the next iteration usingcontinue. - Maintains the order of elements as defined in the array. - Suitable for scenarios where you need more control over the loop, such as terminating early or skipping specific elements. Example usage offor...of:

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const numbers = [1, 2, 3, 4];
for (const number of numbers) {
  console.log(number);
}

In summary,forEach() is a higher-level abstraction that simplifies iterating over arrays and executing a callback function for each element. It provides a concise syntax but does not support breaking out of the loop. On the other hand,for...of gives you more control over the loop and allows you to usebreak andcontinue statements. It is suitable for situations where you need more fine-grained control over the iteration process.

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