Angular 从 json 中获取随机密钥

Question

我想知道如何通过对象内部的名称获取键的值。

示例：我传递了标题“Black”的名称，它们在 json 对象中返回 pk 值“170238”

api.service.ts

import { HttpClient } from "@angular/common/http";
import { Injectable } from "@angular/core";

@Injectable({
  providedIn: "root",
})
export class ApiService {
  private readonly API_URL = "xxx";
  private readonly header_job = { Authorization: "Token" };
  private parData: any = { ref_number: "4806" };
  constructor(private http: HttpClient) {}


  jobStates(ref_number: string) {
    this.parData = { ref_number };
    return this.http.get(`${this.API_URL}/combo/jobs/jobstates/?ref_number=${ref_number}`, {
      headers: { ...this.header_job },
    });
  }

API 的结果

[
    {
        "order": 0,
        "title": "Brown",
        "pk": 170231
    },
    {
        "order": 1,
        "title": "Black",
        "pk": 170238
    },
    {
        "order": 2,
        "title": "White",
        "pk": 170239
    },
    {
        "order": 3,
        "title": "Blue",
        "pk": 170240
    },
    {
        "order": 4,
        "title": "Red",
        "pk": 170241
    },
    {
        "order": 5,
        "title": "Yellow",
        "pk": 170242
    }
]

Answer 1

您可以使用.find()函数获取您需要的数据

this.apiService.jobStates(ref_number).subscribe(response => {
   const job_ref = response.find(r => r.title === title);
   if (job_ref !== undefined) {
      // set variable with job_ref.pk
   }
});

我不知道你具体想如何设置数据，所以我使用了 Observable 实现。

myFunction() {
    getPkValueByTitle(this.ref_number, this.title).subscribe(pk => {
        // set variable with pk
    });
}

getPkValueByTitle(ref_number, title: string): Observable<any> {
    return new Observable<any>(observer => {
        this.apiService.jobStates(ref_number).subscribe(response => {
            const job_ref = response.find(r => r.title === title);
            if (job_ref !== undefined) {
                observer.next(job_ref.pk);
            } else {
                observer.next(null);
            }
            observer.complete();
        });
    });
}

编辑：或者您可以使用.filter() 函数仅返回您需要的内容。请注意，这是未经测试的代码，因此可能需要一些调整

  jobStates(ref_number: string, title: string) {
    this.parData = { ref_number };
    return this.http.get(`${this.API_URL}/combo/jobs/jobstates/?ref_number=${ref_number}`, {
      headers: { ...this.header_job },
    }).filter(value => value.title === title);
  }