TypeError: Klasse erweitert Wert undefined ist keine Funktion oder null

Question

Ich bekomme den folgenden Fehler beim Versuch, diese Entitäten zu erstellen.

TypeError: Class extends value undefined is not a function or null

Ich gehe davon aus dem etwas mit zirkulären Abhängigkeiten zu tun hat, aber wie soll das denn vermeiden, wenn die Tabelle Vererbung und eine zu viele Beziehungen mit?

Es beschwert sich über das folgende Javascript bei BaseComic_1.BaseComic.

let Variant = class Variant extends BaseComic_1.BaseComic {

Dies ist die komplette Datei.

"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; 
} 

Answer 1

ich das gleiche Problem hatte. Es stellte sich heraus, dass ich zirkulär Klassen importierte, was anscheinend eine Einschränkung ist.

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