Expo TypeORM EntityMetadataNotFoundError

Question

我正在尝试通过驱动程序 expo-sqlite 在 expo 项目上使用 typeorm，但我一直坚持这个元数据

EntityMetadataNotFoundError: No metadata for "User" was found.

错误。据我了解

entities: [User]

上的这一行

config.ts

它与错误有关，搜索它我发现一些人们讨论实体上的错误配置，但他们直接指向文件系统路径，并且我' m 通过DataSource 传递User 类。我根据 This repo 和 TypeORM 编写了这段代码，奇怪吗？例子

我已经尝试过了：

entities: ['./entities/*.entity.ts']

错误堆栈

[Unhandled promise rejection: EntityMetadataNotFoundError: No metadata for "User" was found.]
at http://192.168.2.2:19000/node_modules/expo/AppEntry.bundle?platform=ios&dev=true&hot=false&strict=false&minify=false:166214:321 in _createSuperInternal
at node_modules/typeorm/browser/error/TypeORMError.js:5:25 in constructor
at http://192.168.2.2:19000/node_modules/expo/AppEntry.bundle?platform=ios&dev=true&hot=false&strict=false&minify=false:167099:321 in _createSuperInternal
at node_modules/typeorm/browser/error/EntityMetadataNotFoundError.js:5:24 in constructor
at node_modules/typeorm/browser/data-source/DataSource.js:281:8 in getMetadata
at node_modules/typeorm/browser/repository/Repository.js:19:19 in get__metadata
at node_modules/typeorm/browser/repository/Repository.js:72:9 in save
at App.tsx:31:18 in wrapper
at App.tsx:25:8 in wrapper
at App.tsx:33:15 in useEffect$argument_0
at node_modules/react-native/Libraries/ReactNative/renderApplication.js:58:4 in renderApplication
at node_modules/react-native/Libraries/ReactNative/AppRegistry.js:117:25 in runnables.appKey.run
at node_modules/react-native/Libraries/ReactNative/AppRegistry.js:202:4 in runApplication

import { Entity, PrimaryGeneratedColumn, Column, BaseEntity } from "typeorm"

@Entity('user')
export class User extends BaseEntity {

    @PrimaryGeneratedColumn()
    id: number

    @Column()
    firstName: string

    @Column()
    lastName: string

    @Column()
    age: number
}

import "reflect-metadata"
import * as SQLite from 'expo-sqlite'
import { DataSource, DataSourceOptions } from "typeorm/browser"

import { User } from "./entities/User.entity"


export const AppDataSourceOptions: DataSourceOptions = {
    type: 'expo',
    database: 'zipzop.db',
    driver: SQLite,
    synchronize: true,
    logging: false,
    entities: [User],
    migrations: [],
    subscribers: [],
}


export const AppDataSource = new DataSource(AppDataSourceOptions)

import React, { useEffect } from 'react';
import { StatusBar } from 'expo-status-bar';
import { SafeAreaProvider } from 'react-native-safe-area-context';

import useCachedResources from './src/hooks/useCachedResources';
import useColorScheme from './src/hooks/useColorScheme';
import Navigation from './src/navigation';


import { AppDataSource } from './src/database/config';
import { User } from './src/database/entities/User.entity'


export default function App(props : any) {
    useEffect(() => {
        if(!AppDataSource.isInitialized){
            AppDataSource.initialize()
            .then(() => console.log("Database initialization SUCESS"))
            .catch((err) => console.log("Database initialization FAILED", err))
            .finally(async () => {
            })
        } else {
            console.log("Database initialization ALREADY")
        }
        async function wrapper() {
            let repository = AppDataSource.getRepository(User)
            let user = new User()
            user.firstName = "Francisco"
            user.lastName = "Pena"
            user.age = 24
            await repository.save(user)
        }
        wrapper()

        async function wrapper2() {
            let repository = AppDataSource.getRepository(User)
            const allUsers = await repository.find()
            console.log(allUsers)
        }
    })


    const isLoadingComplete = useCachedResources();
    const colorScheme = useColorScheme();

    if (!isLoadingComplete) {
        return null;
    } else {
        return (
            <SafeAreaProvider>
            <Navigation colorScheme={colorScheme} />
            <StatusBar />
            </SafeAreaProvider>
            );
    }
}

存储库出现错误

Answer 1

我有同样的问题，看看https://github.com/typeorm/expo-example/pull/5

typeorm 的展会示例刚刚更新

Answer 2

发生此错误的原因是某些导入在完全初始化之前使用了 TypeORM 数据源中的资源。

请记住，所有导入的模块都会在模块主体之前进行评估，正如此 SO 答案中所述：ES6 导入的定义执行顺序是什么？

您的代码存储库缺少某些部分，例如“types”文件夹，因此我无法正确检查您的所有导入。但记住这一点很重要。

现在，回到上面的代码，从我可以看到

useEffect

脚本中的

app.ts

挂钩初始化了

AppDataSource

，但这是一个将异步执行的 Promise。之后，无需等待 Promise 完成执行，您就可以通过

wrapper()

调用正在使用未启动存储库的

let repository = AppDataSource.getRepository(User)

函数。此代码可能是错误的原因。

在这种情况下，您应该添加一个控制状态变量，您将在“then”部分设置该变量

AppDataSource.initialize()

。在初始化过程正确完成后，该控制变量将触发其他代码，例如

wrapper()

函数内的代码。