如何实现发起异步DB请求的SvelteKit POST接口并解决返回404问题

我访问SvelteKit POST接口时，如果提交的参数未通过校验，接口可以正常返回正确的状态码和响应体。但执行DB插入操作时，尽管用户数据成功写入数据库，接口却返回404错误。我推测原因是DB调用为异步操作，SvelteKit没有等待结果返回，但不知道如何修改代码才能让接口等待异步执行完成后返回正确的JSON响应。

感谢大家的帮助！

import type { EndpointOutput } from '@sveltejs/kit';
import bcrypt from 'bcrypt';
import { randomUUID } from 'crypto';
import db from '$lib/config/db.js';
import { roles } from '$lib/config/roles.js';
import validation from '$lib/_helpers/validation';

export async function post({
    body
}: {
    body: { firstName: string; lastName: string; emailAddress: string; password: string };
}): Promise<EndpointOutput> {
    // 去除字段首尾空白字符
    console.log(body);
    const firstName = body?.firstName.trim();
    const lastName = body?.lastName.trim();
    const email = body?.emailAddress.trim();
    const password = body?.password.trim();
    const userRole = roles.web + roles.anonymous;
    const bcryptPassword = await bcrypt.hash(password, 10);
    const emailToken = randomUUID();
    // 二次校验字段，防止用户直接调用接口提交数据
    if (validation.validateEmail(email) == false) {
        //console.log(email);
        return {
            status: 422,
            body: {
                message: '请输入合法的邮箱地址'
            }
        };
    }
    if (validation.validatePassword(password) == false) {
        return {
            status: 422,
            body: {
                message: '密码长度至少为6位'
            }
        };
    }
    if (validation.validateNotEmpty(firstName) == false) {
        return {
            status: 422,
            body: {
                message: '请填写名字'
            }
        };
    }
    if (validation.validateDisplayName(lastName) == false) {
        return {
            status: 422,
            body: {
                message: '请填写姓氏'
            }
        };
    }

// 插入用户数据
    await db.query(
        'INSERT INTO users (first_name, last_name, email, user_password, user_role, email_verification_token) VALUES ($1, $2, $3, $4, $5, $6)',
        [firstName, lastName, email, bcryptPassword, userRole, emailToken],
        (error, results) => {
            // console.log(error, results);
            if (error) {
                return {
                    status: 417,
                    body: {
                        message: error.toString()
                    }
                };
            }
            //console.log(results);
            return {
                status: 201,
                body: {
                    message: '用户创建成功'
                }
            };
        }
    );
}

我最终改用pg-promise包而非pg包来连接数据库，以下是更新后的代码，可供遇到同类问题的开发者参考：

import type { EndpointOutput } from '@sveltejs/kit';
import bcrypt from 'bcrypt';
import { randomUUID } from 'crypto';
import { roles } from '$lib/config/roles.js';
import validation from '$lib/_helpers/validation';
import { db } from '$lib/config/db.js';

export async function post({
    body
}: {
    body: { firstName: string; lastName: string; emailAddress: string; password: string };
}): Promise<EndpointOutput> {
    // 去除字段首尾空白字符
    console.log(body);
    const firstName = body?.firstName.trim();
    const lastName = body?.lastName.trim();
    const email = body?.emailAddress.trim();
    const password = body?.password.trim();
    const userRole = roles.web + roles.anonymous;
    const bcryptPassword = await bcrypt.hash(password, 10);
    const emailToken = randomUUID();
    // 二次校验字段，防止用户直接调用接口提交数据
    if (validation.validateEmail(email) == false) {
        //console.log(email);
        return {
            status: 422,
            body: {
                message: '请输入合法的邮箱地址'
            }
        };
    }
    if (validation.validatePassword(password) == false) {
        return {
            status: 422,
            body: {
                message: '密码长度至少为6位'
            }
        };
    }
    if (validation.validateNotEmpty(firstName) == false) {
        return {
            status: 422,
            body: {
                message: '请填写名字'
            }
        };
    }
    if (validation.validateDisplayName(lastName) == false) {
        return {
            status: 422,
            body: {
                message: '请填写姓氏'
            }
        };
    }

    // 检查用户是否已存在
    const userAlreadyExists = await db.oneOrNone('SELECT email from users WHERE email=$1 LIMIT 1', [
        email
    ]);
    console.log(' result: ' + userAlreadyExists);
    if (userAlreadyExists) {
        return {
            status: 409,
            body: {
                message: '该邮箱对应的用户已存在'
            }
        };
    }

    try {
        // 向DB插入新用户数据
        await db.none(
            'INSERT INTO users (first_name, last_name, email, user_password, user_role, email_verification_token) VALUES ($1, $2, $3, $4, $5, $6)',
            [firstName, lastName, email, bcryptPassword, userRole, emailToken]
        );

        return {
            status: 201,
            body: {
                message: '用户创建成功'
            }
        };
    } catch (error) {
        return {
            status: 417,
            body: {
                message: error.toString()
            }
        };
    }
}

内容的提问来源于stack exchange，提问作者Jeff McMorris