Two main reasons stand out:
The forEach method completely disregards the value returned from its callback function
You are not implementing any actions to update the variable value
If your intention is to alter the contents of value, you have two options:
value = value.map(element => element + 2);
This approach creates a new array and assigns it to the variable value; bear in mind that variable b remains unchanged. This mimics the behavior of value += 2 in the alternative path, which similarly does not affect variable
b</code at all.</p>
<p>You can also opt for this method:</p>
<pre><code>value.forEach((element, index) => {
value[index] = element + 2;
});
Here, the original array (stored in variable b) is modified directly. However, this method does not match the behavior outlined in the alternate branch, where b is left unaltered.
However, if you aim to modify variable b, consistency is key. As shared by Kobe here, using map is commonly preferred as it generates a new array - often the desired outcome. Should you prefer updating the existing array instead, consider the following method:
const b = [1, 2, 3, [4, 5], 6];
for (const [bIndex, value] of b.entries()) {
if (Array.isArray(value)) {
for (const [vIndex, entry] of value.entries()) {
value[vIndex] = entry + 2;
}
} else {
b[bIndex] = value + 2;
}
}
console.log(`b = ${JSON.stringify(b)}`);
While Kobe's solution using map is typically recommended, unless there is a compelling reason to update in place.