"Arranging an object" may be a more accurate way to describe the process you are explaining. In most cases, the order of keys in an object is not essential. Objects, as well as Maps and Dictionaries, are not ideal for storing collections in a sorted manner. It is recommended to use an array for this purpose, or use a method like
Array.from(Object.keys(obj)).sort()
if you need to sort the keys of an object
obj.
In order to understand why the code functions as it does, we need to analyze the sortWeekFunction function.
const sortWeekFunction = (array, object) => {
const newMapSortObj = new Map(Object.entries(object));
const sortObj = Array.from(newMapSortObj)?.sort(
(a, b) => array.indexOf(a[0]) - array.indexOf(b[0])
);
return Object.fromEntries(sortObj);
};
Initially, a Map is created from the object's entries. A map is similar to a JavaScript Object, but with some variations. The map is used in the array creation process here:
Array.from(newMapSortObj)
The resulting array will look like this:
[
[ 'wednesday', 'wednesday' ],
[ 'friday', 'friday' ],
[ 'monday', 'monday' ],
[ 'thursday', 'thursday' ],
[ 'sunday', 'sunday' ]
]
It's important to note that this is an "array of arrays."
Next, the array's .sort() method is used with a custom sorting function, defined as a lambda expression here:
sort(
(a, b) => array.indexOf(a[0]) - array.indexOf(b[0])
);
This process essentially compares pairs of elements in the array by evaluating
array.indexOf(a[0]) - array.indexOf(b[0])
. For instance, if
a[0] is
wednesday and
b[0] is
sunday</code, their corresponding indexes from your provided sortArray are compared to determine their order.
</p>
<p>Finally, an object is created from the sorted array entries using <code>Object.fromEntries(sortObj)
and returned.
The end result is an object with keys that are sorted according to the specified criteria.