JavaScript Day 40— Mastering JavaScript Basics: A Comprehensive Guide for Interview Preparation

100 Days of JavaScript Interview Prep: A Beginner’s Journey

Understanding the Sorting in JavaScript ?

Welcome to Day 40–100 Days of JavaScript Interview Prep: A Beginner’s Journey with understanding the Sorting (Sort) in JavaScript.

Answer : Think of sorting in JavaScript like organizing a name of cities in particular order.

Let’s consider some basic rules for sorting

Arrange them alphabetically order

Arrange them based on geographic location

Arrange them based on population size.

Example

// before sorting -arrange them alphbetically order 
["New York", "London", "Paris", "Tokyo", "Beijing"],

// after sorting - alphabetically order
["Beijing", "London", "New York", "Paris", "Tokyo"].

Hope we understand the basic idea’s of sorting in our general approach.

Now, let’s now understand the definition of sorting in our web/tech world.

Sorting or function Sort() | Array.prototype.sort()

The sort() function allows -

To sort an array object by either the default sorting order, or by a custom sorting function.

Syntax

Array.prototype.sort()
sort() // default sorting order ascending

sort(compareFn) // custom sorting function

The default sort order is ascending, built upon converting the elements into strings, then comparing their sequences of UTF-16 code units values.

UTF-16 code units values

1. UTF-16 (16-bit Unicode Transformation Format) is a character encoding that represents Unicode code points using 16-bit code units.

2. In UTF-16, each code unit represents a single 16-bit value.

Example

const alphabets = ['A', 'C', 'B', 'F'];
alphabets.sort();
console.log(alphabets); // (4) ["A", "B", "C", "F"]

const myNumbers = [11, 0, 1, 22, 222222];
myNumbers.sort();
console.log(myNumbers); // (5) [0, 1, 11, 22, 222222]

Getting Started :)

Question 1 — What is the output of below code (values with empty array) ?

let valuesWithEmpty = [3, "", 1,"", 5, "", 2, "", 4];

Answer

Default behavior with empty values sorted to the beginning

let valuesWithEmpty = [3, "", 1,"", 5, "", 2, "", 4];
valuesWithEmpty.sort(); 
console.log(valuesWithEmpty);

Conclusion

In this example, empty strings '' are sorted to the beginning of the array, followed by non-empty strings.

Question 2- What would be output when sorting with null values?

let valuesWithNull = [3, null, 1, null, 5, null, 2, null, 4];

Answer :

In this example, null values are sorted to the end of the array.

let valuesWithNull = [3, null, 1, null, 5, null, 2, null, 4];
valuesWithNull.sort();
console.log(valuesWithNull);

Question 3- What would be output when sorting with null values and empty string?

let valuesWithNulEmpty = [3, null, 1, "", 5, "", 2, "", 4];

Answer :

In this example, empty strings '' are sorted to the beginning of the array, followed by non-empty strings and empty null values are sorted to the end of the array.

let valuesWithNulEmpty = [3, null, 1, "", 5, "", 2, "", 4];
valuesWithNulEmpty.sort();
console.log(valuesWithNulEmpty);

Question 4 -What would be output when sorting with non-empty, null values and empty string?

let valuesWithNulEmptyString = [3, null, 1, "kk", 5, "", 2, "", 4];

Answer —

In this example, empty strings '' are sorted to the beginning of the array, followed by non-empty strings and empty null values are sorted to the end of the array.

let valuesWithNulEmptyString = [3, null, 1, "kk", 5, "", 2, "", 4];
valuesWithNulEmptyString.sort();
console.log(valuesWithNulEmptyString);

Question 5-What would be output when sorting with non-empty, null values, undefined and empty string?

let valuesWithNulEmptyStringUndefiend = [3, null, 1, "kk", 5, "", 4,undefined];

Answer :

In this example, empty strings '' are sorted to the beginning of the array, followed by non-empty strings and empty null values, undefined are sorted to the end of the array.

let valuesWithNulEmptyStringUndefiend = [3, null, 1, "kk", 5, "", 4,undefined];
valuesWithNulEmptyStringUndefiend.sort();
console.log(valuesWithNulEmptyStringUndefiend);

Tomorrow we will learn more about Sorting with Custom function approach.

Happy Coding and Stay Tuned :)

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