Angular：变量未定义，但为什么呢？

Question

由于某种原因，我似乎正在获取“未定义测试”。我已经在另一个服务文件中定义了与此完全相同的变量。只想知道为什么在特定代码中不起作用？

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';

@Injectable()
export class OnlineTestService {
 // add setters and gettrers  according to your usage
    constructor(private http: HttpClient) {
        var test = "";
        this.getJSON().subscribe(data => {
            return data;
        });
        this.getANSWERS().subscribe(data => {
            return data;
        });

    };

    questionAnswers(input){
        test = input;
    };
    retrieveAnswers(){
        return test;
    };

    public getJSON(): Observable<any> {
        return this.http.get("assets/questions.json");
    };

    public getANSWERS(): Observable<any> {
        return this.http.get("assets/answers.json");
    };

}

Answer 1

在“资产”之前添加斜杠

public getJSON(): Observable<any> {
    return this.http.get("/assets/questions.json");
};

public getANSWERS(): Observable<any> {
    return this.http.get("/assets/answers.json");
};