angular - 如何防止装饰器在 TypeScript 中导入节点模块？

Question

我正在尝试使用 typescript 中的 typeorm 库在 TypeScript 2 Express 服务器和 Angular 2 之间创建 DTO/DAO 模式。

为简洁起见，我将这些对象称为 DTO，但它们只是一堆字段和注释。

import {autoserialize} from "cerialize";
import {DTOReport} from "./reports.dto";

import { PrimaryGeneratedColumn} from "typeorm/decorator/columns/PrimaryGeneratedColumn"
import { CreateDateColumn } from "typeorm/decorator/columns/CreateDateColumn";
import { Column } from "typeorm/decorator/columns/Column";
import { JoinColumn } from "typeorm/decorator/relations/JoinColumn";
import { OneToOne } from "typeorm/decorator/relations/OneToOne";
import { ManyToOne } from "typeorm/decorator/relations/ManyToOne";
import { OneToMany } from "typeorm/decorator/relations/OneToMany";
import { Table } from "typeorm/decorator/tables/Table";
import { ColumnTypes } from "typeorm/metadata/types/ColumnTypes";

@Table()
export class DTOSourceFile {
  @PrimaryGeneratedColumn()
  @autoserialize
  id: number;

  @Column()
  @autoserialize
  locationURL: string;

  @CreateDateColumn()
  @autoserialize
  createdAt: Date;

  @OneToMany(type => DTOReport, report => report.source, {nullable: true})
  @autoserialize report: DTOReport;
  @autoserialize reportId: number;

  @Column(ColumnTypes.TEXT)
  @autoserialize
  originalname: string;

  @Column(ColumnTypes.JSON)
  @autoserialize
  mutler: string;
}

我小心翼翼地只导入装饰器。但是，在编译时我看到一个请求返回到根 index.ts 文件。

"use strict";
const ColumnTypes_1 = require("../../metadata/types/ColumnTypes");
const ColumnTypeUndefinedError_1 = require("../error/ColumnTypeUndefinedError");
const index_1 = require("../../index");  // < --- THIS
const PrimaryColumnCannotBeNullableError_1 = require("../error/PrimaryColumnCannotBeNullableError");
/**
 * Column decorator is used to mark a specific class property as a table column.
 * Only properties decorated with this decorator will be persisted to the database when entity be saved.
 * Primary columns also creates a PRIMARY KEY for this column in a db.
 */
function PrimaryColumn(typeOrOptions, options) {
    let type;
    if (typeof typeOrOptions === "string") {
        type = typeOrOptions;
    }
    else {
        options = typeOrOptions;
    }
    return function (object, propertyName) {
        const reflectedType = ColumnTypes_1.ColumnTypes.typeToString(Reflect.getMetadata("design:type", object, propertyName));
        // if type is not given implicitly then try to guess it
        if (!type)
            type = ColumnTypes_1.ColumnTypes.determineTypeFromFunction(Reflect.getMetadata("design:type", object, propertyName));
        // if column options are not given then create a new empty options
        if (!options)
            options = {};
        // check if there is no type in column options then set type from first function argument, or guessed one
        if (!options.type)
            options = Object.assign({ type: type }, options);
        // if we still don't have a type then we need to give error to user that type is required
        if (!options.type)
            throw new ColumnTypeUndefinedError_1.ColumnTypeUndefinedError(object, propertyName);
        // check if column is not nullable, because we cannot allow a primary key to be nullable
        if (options.nullable)
            throw new PrimaryColumnCannotBeNullableError_1.PrimaryColumnCannotBeNullableError(object, propertyName);
        // implicitly set a primary to column options
        options = Object.assign({ primary: true }, options);
        // create and register a new column metadata
        const args = {
            target: object.constructor,
            propertyName: propertyName,
            propertyType: reflectedType,
            mode: "regular",
            options: options
        };
        index_1.getMetadataArgsStorage().columns.add(args); // < --- THIS
    };
}
exports.PrimaryColumn = PrimaryColumn;

//# sourceMappingURL=PrimaryColumn.js.map

Angular 2 的 webpack 编译器产生的错误清楚地显示了问题，因为它随后尝试加载节点依赖项。

WARNING in ./~/typeorm/driver/sqlserver/SqlServerDriver.js
Module not found: Error: Can't resolve 'mssql' in '/Users/jmurphy/projects/ubq/web/node_modules/typeorm/driver/sqlserver'
 @ ./~/typeorm/driver/sqlserver/SqlServerDriver.js 256:25-41
 @ ./~/typeorm/connection/ConnectionManager.js
 @ ./~/typeorm/index.js
 @ ./~/typeorm/decorator/columns/PrimaryGeneratedColumn.js
 @ ./src/app/dtos/lens.dto.ts
 @ ./src/app/lens/lens.component.ts
 @ ./src/app/app.module.ts
 @ ./src/app/index.ts
 @ ./src/main.ts
 @ multi main
Child html-webpack-plugin for "index.html":
         Asset     Size  Chunks       Chunk Names
    index.html  2.88 kB       0
webpack: bundle is now VALID.

有没有办法允许 TypeORM 装饰器存在于浏览器项目中而无需尝试加载节点依赖项？

链接:

TypeORM 来源: https://github.com/typeorm/typeorm/blob/master/src/decorator/columns/PrimaryColumn.ts

Answer 1

我认为这个库不是为在网络浏览器中工作而设计的，但也许有一个解决方案。装饰器使用在 /index.ts 中声明的 getMetadataArgsStorage 函数。 /index.ts 导入了很多导致您遇到问题的东西。

可以看到here getMetadataArgsStorage 函数如何使用 defaultContainer 和 MetadataArgsStorage。

如果 getMetadataArgsStorage 已从 index.ts 移动到一个新文件，它可能对您有用，但您将需要向 GitHub 上的项目发送 PR。

问题是this line因为 ConnectionManager 导入所有驱动程序:

import * as fs from "fs";
import {Connection} from "./Connection";
import {ConnectionNotFoundError} from "./error/ConnectionNotFoundError";
import {MysqlDriver} from "../driver/mysql/MysqlDriver";
import {ConnectionOptions} from "./ConnectionOptions";
import {DriverOptions} from "../driver/DriverOptions";
import {Driver} from "../driver/Driver";
import {MissingDriverError} from "./error/MissingDriverError";
import {PostgresDriver} from "../driver/postgres/PostgresDriver";
import {AlreadyHasActiveConnectionError} from "./error/AlreadyHasActiveConnectionError";
import {Logger} from "../logger/Logger";
import {SqliteDriver} from "../driver/sqlite/SqliteDriver";
import {OracleDriver} from "../driver/oracle/OracleDriver";
import {SqlServerDriver} from "../driver/sqlserver/SqlServerDriver";
import {OrmUtils} from "../util/OrmUtils";
import {CannotDetermineConnectionOptionsError} from "./error/CannotDetermineConnectionOptionsError";

/**
 * ConnectionManager is used to store and manage all these different connections.
 * It also provides useful factory methods to simplify connection creation.
 */
export class ConnectionManager {
// ...

我建议您向 typeorm 的作者解释您的用例。也可以提到，如果不是所有的驱动程序都默认导入，那将是很好的。最好只加载所需的驱动程序(在你的情况下没有)。