How to work with Structs in JavaScript ?

Structs are typically found in languages like C, C++, and similar, and they provide a way to organize related data items under one name. Typically JavaScript does not have built-in support for structs, but you can achieve similar functionality using objects. Objects in JavaScript are dynamic collections of key-value pairs, where keys are strings (or Symbols) and values can be any data.

Using Objects

To create a struct-like object using plain objects, you define an object literal with properties representing the fields of the struct. Each property is defined as a key-value pair, where the key is the name of the property and the value is the corresponding data.

Example: Explanation of Structs in JavaScript Using Objects.

JavaScript

const person = {
    name: 'John Doe',
    age: 30,
    occupation: 'Engineer',
    city: 'New York'
};

// Accessing properties
console.log("Name:", person.name);

// Modifying properties
person.age = 35;

// Adding new properties
person.country = 'USA';

// Deleting existing value 
delete person.city

// Final output 
console.log('Person', person); 

Output

Name: John Doe
Person { name: 'John Doe', age: 35, occupation: 'Engineer', country: 'USA' }

Using ES6 Classes

To create a struct-like object using ES6 classes, you define a class using the class keyword, followed by the class name. Inside the class, you define a constructor method to initialize the object’s properties and methods. After defining, you can create instances of the class using the new keyword. You can access and manipulate the properties of it using dot notation.

Example: Explanation of Structs in JavaScript Using ES6 Classes.

JavaScript

class Person {
    constructor(name, age, occupation) {
        this.name = name;
        this.age = age;
        this.occupation = occupation;
    }

    // Method to display person's details
    displayDetails() {
        console.log(`Name: ${this.name}, Age: ${this.age},
                     Occupation: ${this.occupation}`);
    }
}

// Creating an instance of Person
const person1 = new Person('John Doe', 30, 'Engineer');
const person2 = new Person('Jane Smith', 25, 'Doctor');

// Accessing properties
console.log("Name:", person1.name); 
console.log("Age:", person2.age);

// Updating properties
person1.name = 'Ram';
person2.age = 45;

// Calling method to display details
person1.displayDetails();
person2.displayDetails();

Output

Name: John Doe
Age: 25
Name: Ram, Age: 30, Occupation: Engineer
Name: Jane Smith, Age: 45, Occupation: Doctor

Using String Split()

To create a struct-like behavior in JavaScript, Start with structured data as a string. Then use split() to break the string into parts. After that assign parts to object properties for a struct-like object.

Example: Explanation of Structs in JavaScript Using String Split().

JavaScript

// Define a string representing structured data
const personData = "John,Doe,30";

// Split the string into an array
const dataArray = personData.split(',');

// Create a struct-like object using an object literal
const person = {
    firstName: dataArray[0],
    lastName: dataArray[1],
    age: Number(dataArray[2])
};

console.log(person); 

Output

{ firstName: 'John', lastName: 'Doe', age: 30 }

Using the ‘this’ Keyword in Class

In a class in JavaScript, the ‘this’ keyword refers to the current instance of the class. It typically refers to the class that is currently being constructed by a constructor function.

Example: Explanation of Structs in JavaScript Using the ‘this’ Keyword in Class.

JavaScript

class Person {
    constructor(name, age) {
        this.name = name;
        this.age = age;
    }

    greet() {
        console.log(`Hello, my name is ${this.name}
                     and I am ${this.age} years old.`);
    }
}

const john = new Person('John', 30);
john.greet(); 

Output

Hello, my name is John and I am 30 years old.

Using the ‘this’ Keyword in Object

The ‘this’ keyword in JavaScript refers to the current object context within which the code is executed. It typically refers to the object on which a method is called.

Example: Explanation of Structs in JavaScript Using the ‘this’ Keyword in Object.

JavaScript

const person = {
    name: 'John',
    greet: function () {
        console.log('Hello, my name is ' + this.name);
    }
};

person.greet();

Output

Hello, my name is John