获取数据而无需在angular5中重新加载页面

Question

我想显示更新的数据而无需重新加载页面。我使用了Observables，但是没有用。谁能帮忙。我这样尝试过

我的ts文件

tryCatch({
  data2_2 <- data1_2[[j]] %>% html_table(fill = TRUE)
  if (grepl("Annual Income Statement", data2_2[1,1])){

    data2_2 <- data2_2[4:nrow(data2_2),]

    units <- data2_2[1,4]
    units <- substr(units, regexpr("Actuals in ", units) + 11, nchar(units))

    year <- data2_2[2,4]
    fiscal <- data2_2[2,1]

    sales_pos <- grep("Sales", data2_2[,1])
    ebitda_pos <- grep("EBITDA", data2_2[,1])
    ebit_pos <- grep("Operating profit", data2_2[,1])
    ebt_pos <- grep("Pre-Tax Profit", data2_2[,1])
    net_income_pos <- grep("Net income", data2_2[,1])
    pe_ratio_pos <- grep("P/E ratio", data2_2[,1])
    eps_pos <- grep("EPS", data2_2[,1])

    sales <- as.numeric(gsub(" ", "", data2_2[sales_pos,4]))
    ebitda <- as.numeric(gsub(" ", "", data2_2[ebitda_pos,4]))
    ebit <- as.numeric(gsub(" ", "", data2_2[ebit_pos,4]))
    ebt <- as.numeric(gsub(" ", "", data2_2[ebt_pos,4]))
    net_income <- as.numeric(gsub(" ", "", data2_2[net_income_pos,4]))
    pe_ratio <- as.numeric(gsub(",", ".", data2_2[pe_ratio_pos,4]))
    eps <- (gsub(",", ".", data2_2[eps_pos,4]))
    eps <- as.numeric(gsub(" ", "", eps))

  }
}, error = function(e) {e; error_list_2 <<- c(error_list_2, j)})

我的服务

cat_update() {
    let data= {
      id: this.catdata[0]._id,
      category_name:this.category_name
    }

    this.accountService.updatecategory(data).subscribe(response => {
      alert("successfully updated")
    }, err => {
      alert("Something went wrong while update");
    })
}

我的html文件

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { DataService } from './data.service';
import { Observable } from 'rxjs';
import {map} from 'rxjs/operators';

@Injectable({
  providedIn: 'root'
})
export class AccountService {
  public apiPath: string;

  constructor(ds: DataService, public http: HttpClient) {
    this.apiPath = ds.apiPath;
   }
   public dt(res:Response){
    return res;
  }

  updatecategory(data): Observable<any> {
    return this.http.post(this.apiPath + 'user/updatecategory', 
      data)
    .pipe(map(this.dt)));
  }

在我的html中，我编写了一种用于更新和添加类别部分的方法。更新和添加到数据库很好。但是我需要更新的数据而无需重新加载页面。