javascript-TypeError:类扩展未定义的值不是函数或null
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![javascript-TypeError:类扩展未定义的值不是函数或null](/upload/InfoBanner/zyjiaocheng/695/682b210cedcd4aa8b9cd86a3b8199b64.jpg)
尝试创建这些实体时出现以下错误.
TypeError:类扩展未定义的值不是函数或null
我假设这与循环依赖关系有关,但是在使用表继承和一对多关系时应该如何避免呢?
它在BaseComic_1.BaseComic上抱怨以下javascript.
let Variant = class Variant扩展BaseComic_1.BaseComic {
这是完整的文件.
"use strict";
var __decorate = (this && this.__decorate) || function (decorators, target, key, desc) {
var c = arguments.length, r = c < 3 ? target : desc === null ? desc = Object.getOwnPropertyDescriptor(target, key) : desc, d;
if (typeof Reflect === "object" && typeof Reflect.decorate === "function") r = Reflect.decorate(decorators, target, key, desc);
else for (var i = decorators.length - 1; i >= 0; i--) if (d = decorators[i]) r = (c < 3 ? d(r) : c > 3 ? d(target, key, r) : d(target, key)) || r;
return c > 3 && r && Object.defineProperty(target, key, r), r;
};
var __metadata = (this && this.__metadata) || function (k, v) {
if (typeof Reflect === "object" && typeof Reflect.metadata === "function") return Reflect.metadata(k, v);
};
Object.defineProperty(exports, "__esModule", { value: true });
const typeorm_1 = require("typeorm");
const Comic_1 = require("./Comic");
const BaseComic_1 = require("./BaseComic");
let Variant = class Variant extends BaseComic_1.BaseComic {
};
__decorate([
typeorm_1.ManyToOne(type => Comic_1.Comic, comic => comic.variants),
__metadata("design:type", Comic_1.Comic)
], Variant.prototype, "comic", void 0);
Variant = __decorate([
typeorm_1.ClassEntityChild()
], Variant);
exports.Variant = Variant;
//# sourceMappingURL=Variant.js.map
import {Entity, Column, PrimaryGeneratedColumn, OneToMany} from "typeorm";
import {Comic} from "./Comic";
@Entity()
export class Series {
@PrimaryGeneratedColumn()
public id: number;
@Column("text", {
length: 30
})
public copyright: string;
@Column("text", {
length: 100
})
public attributionText: string;
@Column("text", {
length: 150
})
public attributionHTML: string;
@Column("text", {
length: 50
})
public etag: string;
@Column("text", {
length: 200
})
public title: string;
@Column("text")
public description: string;
@Column("number", {
length: 4
})
public startYear: number;
@Column("number", {
length: 4
})
public endYear: number;
@Column("text", {
length: 20
})
public rating: string;
@Column("text", {
length: 20
})
public type: string;
@Column("text")
public thumbnail: string;
@OneToMany(type => Comic, comic => comic.series)
public comics: Array<Comic>;
}
import {Entity, TableInheritance, PrimaryGeneratedColumn, Column, ManyToOne, DiscriminatorColumn} from "typeorm";
import {Series} from "./Series";
@Entity()
@TableInheritance("class-table")
@DiscriminatorColumn({ name: "type", type: "string"})
export class BaseComic {
@PrimaryGeneratedColumn()
public id: number;
@Column("text", {
length: 30
})
public copyright: string;
@Column("text", {
length: 100
})
public attributionText: string;
@Column("text", {
length: 150
})
public attributionHTML: string;
@Column("text", {
length: 50
})
public etag: string;
@Column("text", {
length: 200
})
public title: string;
@Column("int")
public issue: number;
@Column("text")
public variantDescription: string;
@Column("boolean")
public variant: boolean;
@Column("text")
public description: string;
@Column("int")
public pageCount: number;
@Column("date")
public onSaleDate: Date;
@Column("date")
public unlimitedDate: Date;
@Column("text")
public thumbnail: string;
@ManyToOne(type => Series, series => series.comics)
public series: Series;
}
import {OneToMany, ClassEntityChild} from "typeorm";
import {Variant} from "./Variant";
import {BaseComic} from "./BaseComic";
@ClassEntityChild()
export class Comic extends BaseComic {
@OneToMany(type => Variant, variant => variant.comic)
public variants: Variant[];
}
import {ManyToOne, ClassEntityChild} from "typeorm";
import {Comic} from "./Comic";
import {BaseComic} from "./BaseComic";
@ClassEntityChild()
export class Variant extends BaseComic {
@ManyToOne(type => Comic, comic => comic.variants)
public comic: Comic;
}
解决方法:
我有同样的问题.事实证明,我是循环导入类,这显然是一个限制. (请参阅以下GitHub问题:#20361、#4149、#10712)
注意,似乎循环引用也受文件之间的限制,而不仅仅是类型.
参见this其他答案
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