我正在使用MEAN
Stack 构建评分应用程序。我正在尝试通过服务代码将数据库中的项目列表获取到我的 Angular 组件中,但我一直在获取core.js:14597 ERROR TypeError: Cannot read property 'map' of undefined
.
//scoring.service.js
import { Scoring } from './scoring.model';
import { Injectable } from '@angular/core';
import { Subject } from 'rxjs';
import { map } from 'rxjs/operators';
import { HttpClient } from '@angular/common/http';
import { Router } from '@angular/router';
@Injectable({providedIn: 'root'})
export class ScoringService {
private scoring: Scoring[] = [];
private updatedScores = new Subject<Scoring[]>();
constructor(private http: HttpClient, private router: Router){}
getScoring() {
this.http.get<{message: string, scores: any}>('http://localhost:3000/api/scoring')
.pipe(map((scoringData) => {
return scoringData.scores.map(score => {
status = score.IsActive ? 'checked' : 'unchecked';
return {
id: score._id,
Criteria: score.Criteria,
MaxPoints: score.MaxPoints,
IsActive: status,
DateCreated: score.DateCreated,
DateModified: score.DateModified
};
});
}))
.subscribe((transformedScores) => {
this.scoring = transformedScores;
this.updatedScores.next([...this.scoring]);
});
}
}
该代码应该列出项目并分别从或映射到已选中或未选中的boolean
字段。但根本没有列出任何内容。我得到的错误是并且我在另一个组件中使用了相同的代码集来列出项目而没有收到错误。请在这里帮助我,我将不胜感激。谢谢。true
false
"Cannot read property 'map' of undefined."