Зміст курсу
JavaScript Data Structures
1. Introduction and Prerequisites
2. Objects Fundamentals
3. Advanced Object Manipulation
JavaScript Data Structures
sort() Method
This chapter explores the intricacies of the sort() method, including its syntax, default behaviors, and custom sorting techniques.
sort()
The sort() method modifies the original array, imbuing it with a new arrangement.
Key characteristics to remember:
- The original array transforms, finding its elements in a new arrangement;
- The method furnishes a modified array as its return value, allowing for further exploration;
- By default, the sort() method arranges elements in ascending order.
Default Sorting Behavior
Default sorting unfolds seamlessly for arrays of strings, but numeric arrays might present challenges. Let's navigate through examples to illuminate this behavior:
In this example, the array of numbers is sorted in ascending order, seemingly straightforward. However, nuances emerge in the subsequent illustration:
The sort() method treats elements as strings by default, which can lead to unexpected results. For instance, 19 is sorted before 2, and 25 before 3. The solution lies in customizing the sorting process.
Custom Sort Orders
To tailor sorting to specific needs, a callback function is employed. This function, often called a compare function, dictates the sorting logic. Let's explore custom sorting for both numbers and strings. Basic syntax:
ais considered as the first element;bis considered as the second element.
Sort Numbers
In this instance, the compare function dictates ascending and descending orders based on the relationship between elements a and b.
Code Explanation
[...numbers]: This creates a shallow copy of the original array using the spread
operator. It prevents the original array (numbers) from being modified;
.sort((a, b) => a - b): This sorts the copied array in ascending order. The
sort method takes a comparison function as an argument, and
(a, b) => a - b ensures that elements are arranged in ascending order;
ascendingNumbers.[...numbers]: Again, this creates a shallow copy of the original array to avoid
modifying it;
.sort((a, b) => b - a): This time, the comparison function
(a, b) => b - a sorts the array in descending order by returning a positive value
when b should come before a;
descendingNumbers.Sort Strings
The localeCompare() method facilitates alphabetical sorting, allowing customization for both ascending and descending orders.
Code Explanation
[...employees]: This creates a shallow copy of the original array using the
spread operator to avoid modifying the original array;
.sort((a, b) => a.localeCompare(b)): The sort method is used with a
comparison function (a, b) => a.localeCompare(b). The
localeCompare method is a string comparison method that returns a negative number
if a should come before b in alphabetical order, 0 if they are
equal, and a positive number if a should come after b;
inAlphabetOrder.[...employees]: Another copy of the original array is created to avoid modifying
it;
.sort((a, b) => b.localeCompare(a)): The comparison function is now
(a, b) => b.localeCompare(a), which sorts the array in reverse alphabetical
order;
inReversedOrder.Все було зрозуміло?
Зміст курсу
JavaScript Data Structures
1. Introduction and Prerequisites
2. Objects Fundamentals
3. Advanced Object Manipulation
JavaScript Data Structures
sort() Method
This chapter explores the intricacies of the sort() method, including its syntax, default behaviors, and custom sorting techniques.
sort()
The sort() method modifies the original array, imbuing it with a new arrangement.
Key characteristics to remember:
- The original array transforms, finding its elements in a new arrangement;
- The method furnishes a modified array as its return value, allowing for further exploration;
- By default, the sort() method arranges elements in ascending order.
Default Sorting Behavior
Default sorting unfolds seamlessly for arrays of strings, but numeric arrays might present challenges. Let's navigate through examples to illuminate this behavior:
In this example, the array of numbers is sorted in ascending order, seemingly straightforward. However, nuances emerge in the subsequent illustration:
The sort() method treats elements as strings by default, which can lead to unexpected results. For instance, 19 is sorted before 2, and 25 before 3. The solution lies in customizing the sorting process.
Custom Sort Orders
To tailor sorting to specific needs, a callback function is employed. This function, often called a compare function, dictates the sorting logic. Let's explore custom sorting for both numbers and strings. Basic syntax:
ais considered as the first element;bis considered as the second element.
Sort Numbers
In this instance, the compare function dictates ascending and descending orders based on the relationship between elements a and b.
Code Explanation
[...numbers]: This creates a shallow copy of the original array using the spread
operator. It prevents the original array (numbers) from being modified;
.sort((a, b) => a - b): This sorts the copied array in ascending order. The
sort method takes a comparison function as an argument, and
(a, b) => a - b ensures that elements are arranged in ascending order;
ascendingNumbers.[...numbers]: Again, this creates a shallow copy of the original array to avoid
modifying it;
.sort((a, b) => b - a): This time, the comparison function
(a, b) => b - a sorts the array in descending order by returning a positive value
when b should come before a;
descendingNumbers.Sort Strings
The localeCompare() method facilitates alphabetical sorting, allowing customization for both ascending and descending orders.
Code Explanation
[...employees]: This creates a shallow copy of the original array using the
spread operator to avoid modifying the original array;
.sort((a, b) => a.localeCompare(b)): The sort method is used with a
comparison function (a, b) => a.localeCompare(b). The
localeCompare method is a string comparison method that returns a negative number
if a should come before b in alphabetical order, 0 if they are
equal, and a positive number if a should come after b;
inAlphabetOrder.[...employees]: Another copy of the original array is created to avoid modifying
it;
.sort((a, b) => b.localeCompare(a)): The comparison function is now
(a, b) => b.localeCompare(a), which sorts the array in reverse alphabetical
order;
inReversedOrder.Все було зрозуміло?
