Javascript 如何在typescript中实例化类时自动运行bcrypt代码

正如@akx所提到的，在脚本/类型脚本中使用异步构造函数是不可能的.但是，我们可以通过利用设计模式来绕过这一限制.

让我们探索两个快速的替代方案:

构建器模式

import { v4 as uuidv4 } from 'uuid';
import bcrypt from 'bcryptjs';

class User {
    public userId: string;
    public password: string = '';

    constructor(public userName: string, public plainPassword: string, public email: string) {
        this.userId = uuidv4();
        this.userName = userName;
        this.email = email.toLowerCase();
        this.plainPassword = plainPassword;
    }

    public async hashPassword(): Promise<void> {
        try {
            const salt = await bcrypt.genSalt(10);
            this.password = await bcrypt.hash(this.plainPassword, salt);
        } catch (error) {
            throw error;
        }
    }
}

class UserBuilder {
    private user?: User;

    public initialize(userName: string, plainPassword: string, email: string): UserBuilder {
        this.user = new User(userName, plainPassword, email);
        return this;
    }

    public async build(): Promise<User|null> {
        if (this.user) {
            await this.user.hashPassword();
            return this.user;
        }
        return null;
    }
}

async function clientCode() {
    const user = await new UserBuilder()
        .initialize('John Doe', 'password', 'name@email.com')
        .build();
        
    console.log(user);
}

clientCode();

工厂模式

import { v4 as uuidv4 } from 'uuid';
import bcrypt from 'bcryptjs';

class User {
    public userId: string;
    public password: string = '';

    private constructor(public userName: string, public plainPassword: string, public email: string) {
        this.userId = uuidv4();
        this.userName = userName;
        this.email = email.toLowerCase();
        this.plainPassword = plainPassword;
    }

    public async hashPassword(): Promise<void> {
        try {
            const salt = await bcrypt.genSalt(10);
            this.password = await bcrypt.hash(this.plainPassword, salt);
        } catch (error) {
            throw error;
        }
    }

    // factory method to create a User instance
    public static async createUser(userName: string, plainPassword: string, email: string): Promise<User> {
        const user = new User(userName, plainPassword, email);
        await user.hashPassword();
        return user;
    }
}

// Using the factory method
async function clientCode() {
    const user = await User.createUser('John Doe', 'password', 'name@email.com');
    console.log(user);
}

clientCode();

本质上，这两种模式都允许您控制实例化过程，从而增强代码的可读性和可维护性.虽然这些模式可能不能直接解决JavaScript/Type脚本中缺少异步构造函数的问题，但它们有效地解决了根本问题.