JavaScriptでファクトリー関数を使ったオブジェクト生成の方法と実例

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

const person1 = createPerson('Alice', 30);
const person2 = createPerson('Bob', 25);

person1.greet(); // "Hello, my name is Alice and I am 30 years old."
person2.greet(); // "Hello, my name is Bob and I am 25 years old."

function createPet(name, species) {
    return {
        name: name,
        species: species,
        describe: function() {
            console.log(`This is ${this.name} and it is a ${this.species}.`);
        }
    };
}

const pet1 = createPet('Buddy', 'dog');
const pet2 = createPet('Mittens', 'cat');

pet1.describe(); // "This is Buddy and it is a dog."
pet2.describe(); // "This is Mittens and it is a cat."

function createUser(name, age) {
    return {
        name: name,
        age: age,
        introduce: function() {
            console.log(`Hi, I'm ${this.name} and I'm ${this.age} years old.`);
        }
    };
}

const user1 = createUser('Alice', 28);
const user2 = createUser('Bob', 34);

user1.introduce(); // "Hi, I'm Alice and I'm 28 years old."
user2.introduce(); // "Hi, I'm Bob and I'm 34 years old."

function createCar(make, model) {
    return {
        make: make,
        model: model,
        displayInfo: function() {
            console.log(`This car is a ${this.make} ${this.model}.`);
        }
    };
}

const car1 = createCar('Toyota', 'Corolla');
car1.displayInfo(); // "This car is a Toyota Corolla."

class Car {
    constructor(make, model) {
        this.make = make;
        this.model = model;
    }

    displayInfo() {
        console.log(`This car is a ${this.make} ${this.model}.`);
    }
}

const car2 = new Car('Honda', 'Civic');
car2.displayInfo(); // "This car is a Honda Civic."

class ElectricCar extends Car {
    constructor(make, model, batteryLife) {
        super(make, model);
        this.batteryLife = batteryLife;
    }

    displayBatteryLife() {
        console.log(`This car has a battery life of ${this.batteryLife} hours.`);
    }
}

const eCar = new ElectricCar('Tesla', 'Model S', 12);
eCar.displayInfo(); // "This car is a Tesla Model S."
eCar.displayBatteryLife(); // "This car has a battery life of 12 hours."

function createAccount(initialBalance) {
    let balance = initialBalance; // プライベートプロパティ

    return {
        deposit: function(amount) {
            if (amount > 0) {
                balance += amount;
                console.log(`Deposited: ${amount}. New balance: ${balance}.`);
            }
        },
        withdraw: function(amount) {
            if (amount > 0 && amount <= balance) {
                balance -= amount;
                console.log(`Withdrew: ${amount}. New balance: ${balance}.`);
            } else {
                console.log('Insufficient funds.');
            }
        },
        getBalance: function() {
            console.log(`Current balance: ${balance}.`);
            return balance;
        }
    };
}

const myAccount = createAccount(1000);

myAccount.deposit(500); // "Deposited: 500. New balance: 1500."
myAccount.withdraw(200); // "Withdrew: 200. New balance: 1300."
myAccount.getBalance(); // "Current balance: 1300."
console.log(myAccount.balance); // undefined

function createUser(firstName, lastName) {
    return {
        firstName: firstName,
        lastName: lastName,
        getFullName: function() {
            return `${this.firstName} ${this.lastName}`;
        },
        introduce: function() {
            console.log(`Hello, my name is ${this.getFullName()}.`);
        }
    };
}

const user1 = createUser('John', 'Doe');
const user2 = createUser('Jane', 'Smith');

console.log(user1.getFullName()); // "John Doe"
user1.introduce(); // "Hello, my name is John Doe."

console.log(user2.getFullName()); // "Jane Smith"
user2.introduce(); // "Hello, my name is Jane Smith."

function createTask(title, description, dueDate) {
    return {
        title: title,
        description: description,
        dueDate: dueDate,
        isCompleted: false,
        markAsCompleted: function() {
            this.isCompleted = true;
            console.log(`Task "${this.title}" is completed.`);
        },
        postpone: function(newDate) {
            this.dueDate = newDate;
            console.log(`Task "${this.title}" is postponed to ${this.dueDate}.`);
        },
        printDetails: function() {
            console.log(`Title: ${this.title}\nDescription: ${this.description}\nDue Date: ${this.dueDate}\nCompleted: ${this.isCompleted}`);
        }
    };
}

const task1 = createTask('Finish report', 'Complete the annual report', '2024-08-15');
const task2 = createTask('Buy groceries', 'Milk, Bread, Eggs', '2024-08-05');

task1.printDetails();
// Title: Finish report
// Description: Complete the annual report
// Due Date: 2024-08-15
// Completed: false

task2.printDetails();
// Title: Buy groceries
// Description: Milk, Bread, Eggs
// Due Date: 2024-08-05
// Completed: false

task1.markAsCompleted(); // "Task "Finish report" is completed."
task2.postpone('2024-08-06'); // "Task "Buy groceries" is postponed to 2024-08-06."

function createProject(name, description) {
    const tasks = []; // プライベートなタスクリスト

    return {
        name: name,
        description: description,
        addTask: function(task) {
            tasks.push(task);
            console.log(`Task "${task.title}" added to project "${this.name}".`);
        },
        removeTask: function(taskTitle) {
            const index = tasks.findIndex(task => task.title === taskTitle);
            if (index !== -1) {
                tasks.splice(index, 1);
                console.log(`Task "${taskTitle}" removed from project "${this.name}".`);
            } else {
                console.log(`Task "${taskTitle}" not found in project "${this.name}".`);
            }
        },
        listTasks: function() {
            console.log(`Tasks for project "${this.name}":`);
            tasks.forEach(task => {
                console.log(`- ${task.title}: ${task.description} (Due: ${task.dueDate})`);
            });
        }
    };
}

function createTask(title, description, dueDate) {
    return {
        title: title,
        description: description,
        dueDate: dueDate
    };
}

const project = createProject('Website Redesign', 'Redesign the company website for better UX.');
const task1 = createTask('Design new homepage', 'Create a modern homepage design.', '2024-09-01');
const task2 = createTask('Update CSS styles', 'Refactor and update all CSS styles.', '2024-09-10');

project.addTask(task1);
project.addTask(task2);
project.listTasks();
// Tasks for project "Website Redesign":
// - Design new homepage: Create a modern homepage design. (Due: 2024-09-01)
// - Update CSS styles: Refactor and update all CSS styles. (Due: 2024-09-10)

project.removeTask('Design new homepage');
project.listTasks();
// Tasks for project "Website Redesign":
// - Update CSS styles: Refactor and update all CSS styles. (Due: 2024-09-10)

npm install --save-dev jest

"scripts": {
    "test": "jest"
}

// createUser.js
function createUser(name, age) {
    return {
        name: name,
        age: age,
        introduce: function() {
            return `Hi, I'm ${this.name} and I'm ${this.age} years old.`;
        }
    };
}

module.exports = createUser;

// createUser.test.js
const createUser = require('./createUser');

test('should create a user object with name and age', () => {
    const user = createUser('Alice', 30);
    expect(user.name).toBe('Alice');
    expect(user.age).toBe(30);
    expect(user.introduce()).toBe("Hi, I'm Alice and I'm 30 years old.");
});

test('should introduce the user correctly', () => {
    const user = createUser('Bob', 25);
    expect(user.introduce()).toBe("Hi, I'm Bob and I'm 25 years old.");
});

function createProject(name, description) {
    console.log('Creating project:', name, description);
    const tasks = [];

    return {
        name: name,
        description: description,
        addTask: function(task) {
            tasks.push(task);
            console.log(`Task "${task.title}" added to project "${this.name}".`);
        },
        // その他のメソッド
    };
}

node --inspect-brk createUser.js