NestJSMongoose.find()：檢查是否沒有結果-有解無憂

所以我的問題是，我如何檢查運行時是否沒有結果this.userService.findOne(createUserDto.username);

控制器：

import { Get, Controller, Body, Post, Param } from "@nestjs/common";
import { RegisterService } from "./register.service";
import * as bcrypt from "bcrypt";
import { CreateUserDto } from "./create-user.dto";

@Controller("register")
export class RegisterController {
  constructor(private userService: RegisterService) {}

  @Post()
  create(@Body() createUserDto: CreateUserDto) {
    let chkUname: any = this.userService.findOne(createUserDto.username);

    let response = {
      usernError: "",
      regOk: true,
    };

    if (!chkUname) {
      // this.userService.createUser(createUserDto);
      return chkUname;
    } else {
      // response.usernError = "Sorry, this username is used!";
      // response.regOk = false;
      return true;
    }
  }
  // create(@Param("uname") uname: any) {
  //   return this.userService.findOne(uname);
  // }
}

服務：

import { Injectable, NotFoundException } from "@nestjs/common";
import { InjectModel } from "@nestjs/mongoose";
import { Model } from "mongoose";
import { CreateUserDto } from "./create-user.dto";
import { Users, UsersDocument } from "./schema/user.schema";

@Injectable()
export class RegisterService {
  constructor(
    @InjectModel(Users.name) private readonly usersModel: Model<UsersDocument>
  ) {}

  async createUser(createUserDto: CreateUserDto): Promise<UsersDocument> {
    const user = new this.usersModel(createUserDto);
    return user.save();
  }

  async findOne(uname: string) {
    return this.usersModel.find({uname}).exec();
  }
}

它總是回傳真/假取決于我寫的代碼。

uj5u.com熱心網友回復：

好的 - 我想我發現了幾個問題。

用戶查詢似乎不正確：

  async findOne(uname: string) {
    return this.usersModel.find({uname}).exec();
  }

您沒有包含您的架構，但請確保您正在查詢的欄位實際上是uname（不是username等）。此外，find如果沒有結果，您正在使用 which 將回傳一個空陣列。您應該findOne在查詢中使用

  async findOne(uname: string) {
    // double check that `uname` is the field on your model
    return this.usersModel.findOne({uname: uname}).exec();
  }

第二個問題是在控制器中 - 您不需要等待查詢結果：

let chkUname: any = this.userService.findOne(createUserDto.username);

嘗試

let chkUname = await this.userService.findOne(createUserDto.username)

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標籤：数据库mongodbapi猫鼬巢穴

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