Sharing a variable between an Angular component and a service

I am attempting to pass a variable from a method to a service.

from calibration-detail.component.ts

private heroID: number;
getTheHeroID() {
    this.heroService.getHero(this.hero.id).subscribe(data =>(this.heroID = data.id));
}

to step.service.ts

I am unsure of how to access the variable and store it in another variable. What I want to achieve is:

private test: number = CalibrationDetailComponent.heroID //pass into step.service.ts

or

private test: number = CalibrationDetailComponent.getTheHeroID(); //pass into step.service.ts

What would be the most effective approach to accomplish this?

step.service.ts

import { CalibrationDetailComponent } from './calibration-detail/calibration-detail.component';
import { Injectable }    from '@angular/core';
import { Headers, Http } from '@angular/http';
import { Step } from './step.class';
import { Hero } from './hero.class';
import { Observable } from "rxjs/Rx";
import { ActivatedRoute, Params } from '@angular/router';
import { HeroService } from './hero.service';

@Injectable()
export class StepService {

  hero: Hero;
  private headers = new Headers({'Content-Type': 'application/json'});
  private stepsUrl;  // URL to web api
  private heroID: number;

  constructor (private http: Http, private route: ActivatedRoute, public heroService: HeroService) { 
    //this.heroService.getHero(+['id']).map(data =>(this.heroID = data.id)); //Get the hero id to know which steps to use

  //defaulting to first one
  if (this.heroID = 1){
   this.stepsUrl = 'api/stepsLiftSensor';
 } else if(this.heroID = 2){
   this.stepsUrl = 'api/BucketSensor';
 } else if(this.heroID = 3){
   this.stepsUrl = 'api/EmptyBucketSensor';
 } else if(this.heroID = 4) {
   this.stepsUrl = 'api/FullBucketSensor';
 }
}

  getSteps(): Observable<Step[]> {
    return this.http.get(this.stepsUrl)
               .map(response => response.json().data as Step[]);
  }

  getStep(id: number): Observable<Step> {
    const url = `${this.stepsUrl}/${id}`;
    return this.http.get(url)
      .map(response => response.json().data as Step);
  }

} 

calibration-detail.component.ts

import { Component, OnInit, Input, Output } from '@angular/core';
import { Headers, Http } from '@angular/http';
import { Hero } from '../hero.class';
import { Step } from '../step.class';
import { ActivatedRoute, Params } from '@angular/router';
import { Location } from '@angular/common';
import { InMemoryDataService } from '../in-memory-data.service';
import { HeroService } from '../hero.service';
import { StepService } from '../step.service';
import { Observable } from 'rxjs/Rx';
import 'rxjs/Rx';

@Component({
  moduleId: module.id,
  selector: 'app-calibration-detail',
  templateUrl: './calibration-detail.component.html',
  styleUrls: ['./calibration-detail.component.css']
})

export class CalibrationDetailComponent implements OnInit {
  @Input()
  hero: Hero;
  step: Step;

  private mainStepText: String = "Test" //Main window
  private statusStepText: String = "Calibration Successfull"; //Status window placeholder
  private labelText: String = "Parking Brake Status \nImpl Lockout Switch \nLift Linkage DC";
  private outputText: String = "Disengaged \nLocked Out \n0%";
  private currentStep: number = 0 //Variable for the current step
  private hideThis: boolean = true;
  private heroID: number;

  constructor(
     private heroService: HeroService,
     private stepService: StepService,
     private route: ActivatedRoute,
     private location: Location,
     private http: Http,
  ) { }


  ngOnInit(): void { 
     this.route.params
       .switchMap((params: Params) => this.heroService.getHero(+params['id']))
       .subscribe(hero => this.hero = hero);

     this.route.params
       .switchMap((params: Params) => this.stepService.getStep(+params['id']))
       .subscribe(step => this.step = step);
  }

  goBack() {
    //Goes back to previous step, if there is no previous step it takes you back to location you were at
    if(this.currentStep > 1){
      this.currentStep --;
      this.stepService.getStep(this.currentStep).subscribe(data => (this.mainStepText = data.name));
    } else {
      this.location.back();
    }
  }

  ok() {
    //Placeholder code for now
    this.location.back();
  }

  next() {
    //Assuming there is another step it pulls the next step up, else it says "End of steps"
    if (this.currentStep < 10) { //make sure dont go past number of steps
       this.currentStep ++;
       this.hideThis = false;
       this.stepService.getStep(this.currentStep).subscribe(data => (this.mainStepText = data.name)); //Handles returned observable and sets the data it contains to local variable
  } else {
      this.mainStepText = "End of steps.";
      this.hideThis = true;
    }
  }

  isValid() {
    if (this.currentStep < 1){
      return this.isValid;
    } 
  }

  getTheHeroID() {
    this.heroService.getHero(this.hero.id).subscribe(data =>(this.heroID = data.id));
  }
}

hero.service.ts

import { Injectable }    from '@angular/core';
import { Headers, Http, Response } from '@angular/http';
import 'rxjs/Rx';
import { Hero } from './hero.class';
import { Observable } from "rxjs/Rx";

@Injectable()
export class HeroService {

  private headers = new Headers({'Content-Type': 'application/json'});
  private heroesUrl = 'api/heroes';  // URL to web api

  constructor(private http: Http){ }

  getHeroes(): Observable<Hero[]> {
    return this.http.get(this.heroesUrl)
               .map(response => response.json().data as Hero[]);
  }

  getHero(id: number): Observable<Hero> {
    const url = `${this.heroesUrl}/${id}`;
    return this.http.get(url)
      .map(response => response.json().data as Hero);
  }
}

Answer №1

When you need to pass a value from a component to a service, the process is straightforward:

export class DataTransferService {
    private storedValue: number;

    public setValue(data: number) {
        this.storedValue = data;
    }
}

@Component({
    selector: 'app-data-transfer',
    template: `
        <button (click)="passValueToService(42)"></button>
    `
})
export class DataComponent {

    private inputNumber: number;

    constructor(private _dataTransferService: DataTransferService) {}

    passValueToService(value: number) {
        this._dataTransferService.setValue(value);
    }
}

Answer №2

To transfer the data stored in the "accounts" variable in component.ts to a service, follow these steps:

Firstly, declare a new variable in service.ts file: service.ts:

data : any;

In your component.ts file:

accounts = [];

constructor(){
    this.service.data = this.accounts
}

This will assign the data from the "accounts" variable to the newly created "data" variable in the service.

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

Determining if an object aligns with a specific type in Typescript

Hey there, I've got a little dilemma. Imagine I have a type called A: type A = { prop1: string, prop2: { prop3: string } } Now, let's say I'm getting a JSON object from an outside service and I need to check if that JSO ...

Using ngFor to dynamically populate drop-down options from a key value object in Angular 2

How can I use ngFor in Angular 2 to dynamically populate options in dropdown menus from a key value object? Below is the JSON data: { "employment": { "0": "Employed", "2": "Un-employed", "3": "Retired", "4": "Self" "V ...

Trigger the Material UI DatePicker to open upon clicking the input field

I have a component that is not receiving the onClick event. I understand that I need to pass a prop with open as a boolean value, but I'm struggling to find a way to trigger it when clicking on MuiDatePicker. Here is an image to show where I want to ...

Having trouble with VueJS ref not preventing the default form action on submit?

Within my <script> tag, I currently have the following code: render(createElement) { return createElement("form", {ref: "formEl" , on: {submit: this.handleSubmit} }, [ <insert create form inputs here> ]); } handleSubmit(e) { ...

Ionic 6 prioritizes enhanced accessibility by implementing toast blocks that divert attention away from input fields

Scenario: My form is basic, but when the user tries to submit it with invalid inputs, I show a toast message with an error. Issue: Since upgrading to Ionic 6, I noticed that while the error toast is visible, I am unable to focus on any input fields until ...

Avoid risky assigning value of type `any`

Currently, I am incorporating TypeScript into my client-side application. However, upon running the application, I encounter two specific errors: @typescript-eslint/no-unsafe-assignment: Unsafe assignment of an `any` value. @typescript-eslint/no-unsafe-me ...

Ensure the inferred type is asserted in TypeScript

Is there a more elegant approach to assert the type TypeScript inferred for a specific variable? Currently, I am using the following method: function assertType<T>(value: T) { /* no op */ } assertType<SomeType>(someValue); This technique prov ...

In TypeScript, the type of the second function parameter depends on the type of the first

I'm new to typescript programming. Overview In my typescript react application, I encountered an issue where I needed to dynamically watch the values returned from the watch() method in react-hook-form, based on different parameters passed into a cus ...

I am looking for guidance on removing the bottom line from the ionic 4 segment indicator. Any advice or tips on

.segment-button-indicator { -ms-flex-item-align: end; align-self: flex-end; width: 100%; height: 2px; background-color: var(--indicator-color); opacity: 1; } I am a beginner in hybrid app development and ...

Obtaining data from a BehaviorSubject for numerous dynamically generated components

As I work on developing a dynamic preview feature, I'm experimenting with drag-and-drop functionality to generate components in a canvas. These components can be duplicated within the same canvas, and upon dropping them, settings like styling are appl ...

Encoding URLs in Angular 2 for HTTP POST requests

I am attempting to utilize a service through post with Angular2. Below is my code snippet: var m_dataRequest = this.buildLoginUserPasswordRequest(password, key); let headers = new Headers({ 'Accept': '*/*', &apos ...

The specified property cannot be found on the object type in a Svelte application when using TypeScript

I am attempting to transfer objects from an array to components. I have followed this approach: https://i.stack.imgur.com/HHI2U.png However, it is indicating that the property titledoes not exist in this type. See here: https://i.stack.imgur.com/VZIIg.pn ...

Displaying an array object within an array of objects in Angular 2: A guide

Here is an example of a JSON file: { "id": 5, "url": "http://localhost:8000/api/v1/users/5/", "username": "Najmuddin", "email": "", "groups": [ { "id": 1, "url ": "http://localhost:8000/api/v1/groups/1/", ...

Encountering Build Issue: "NgSemanticModule is not recognized as an NgModule" persists despite inclusion of dependencies and importing into primary module

I have posted my module, component, and package file here. I am attempting to implement a click event with ngif, but I keep encountering an error. The specific error message is "ERROR in NgSemanticModule is not an NgModule". I'm unsure if this error ...

Using TypeScript and controllerAs with $rootScope

I am currently developing an application using Angular 1 and Typescript. Here is the code snippet for my Login Controller: module TheHub { /** * Controller for the login page. */ export class LoginController { static $inject = [ ...

In Next.js, the switch button remains in the same state even after the page is refreshed

Is there a solution for this issue? I am currently developing a switch button for a configuration page. The problem arises when I toggle the switch from active to maintenance mode, save it successfully, but upon refreshing the page, the switch reverts back ...

Why is Zod making every single one of my schema fields optional?

I am currently incorporating Zod into my Express, TypeScript, and Mongoose API project. However, I am facing type conflicts when attempting to validate user input against the user schema: Argument of type '{ firstName?: string; lastName?: string; pa ...

Unlocking keys of JavaScript class prior to class initialization

My constructor was becoming too large and difficult to maintain, so I came up with a solution to start refactoring it. However, even this new approach seemed bulky and prone to errors. constructor(data: Partial<BusinessConfiguration>) { if(!d ...

What is the best way to transfer data from a component to a .ts file that contains an array?

I am currently developing a budgeting application and I have a component that is responsible for holding values that I want to pass to an array stored in a separate file. While I can retrieve data from the array, I am facing difficulty in figuring out how ...

Angular (15) Encountering difficulties in expanding a typed FormGroup

Currently, I am experimenting with typed FormGroup. This is what I have created so far: export interface CustomFormControls { name: FormControl<string|null> content: FormControl<string|null> } export class CustomForm extends FormGroup< ...