Exploring Angular: Embracing the Power of Query String Parameters

Question

Exploring Angular: Embracing the Power of Query String Parameters

I've been struggling with subscribing to query string parameters in Angular 2+. Despite looking at various examples, I can't seem to make it work.

For instance, on this Stack Overflow thread, the question is about obtaining query parameters from a URL in Angular 2+.

Below is the code I have:

import { ActivatedRoute, Router } from '@angular/router';
...
export class MyComponent implements OnInit,OnDestroy {
  private a: boolean = true;
  private b: boolean = true;

  constructor(route: ActivatedRoute)  {
  ...

  ngOnInit(): void {    
    this.route.queryParams.subscribe((queryParams:any) => {
      this.a = queryParams.a;
      this.b = queryParams.b;
     });

The issue I am facing is that 'this' does not seem to point to my component, and setting 'a' and 'b' values which should be used to trigger *ngIf statements does not work as expected.

What could be going wrong?

angular typescript angular-router

Answer 1

Answer №1

Here is the code snippet designed for Angular 5 framework.

import { ActivatedRoute, Router } from '@angular/router';
...
export class MyComponent implements OnInit, OnDestroy {
  private paramA: boolean;
  private paramB: boolean;

  constructor(private route: ActivatedRoute)  {
  this.paramA = true;
  this.paramB = true;
  ...
  }

  ngOnInit(): void {    
    this.route.queryParams.subscribe(queryParams => {
      this.paramA = queryParams['a'];
      this.paramB = queryParams['b'];
  });

Could you please test and confirm if it functions correctly?

Answer 2

Here is the code snippet designed for Angular 5 framework.

import { ActivatedRoute, Router } from '@angular/router';
...
export class MyComponent implements OnInit, OnDestroy {
  private paramA: boolean;
  private paramB: boolean;

  constructor(private route: ActivatedRoute)  {
  this.paramA = true;
  this.paramB = true;
  ...
  }

  ngOnInit(): void {    
    this.route.queryParams.subscribe(queryParams => {
      this.paramA = queryParams['a'];
      this.paramB = queryParams['b'];
  });

Could you please test and confirm if it functions correctly?

Answer 3

Answer №2

Success is on my side...

let component = this;
ngOnInit(): void {
this.route.queryParams.subscribe(queryParams => {
  component.x = queryParams['x'];
  component.y = queryParams['y'];
});

Answer 4

Success is on my side...

let component = this;
ngOnInit(): void {
this.route.queryParams.subscribe(queryParams => {
  component.x = queryParams['x'];
  component.y = queryParams['y'];
});

Answer 5

Answer №3

  initializeComponent() {
    // Example https://example.com?param=value#tag
    this.router.fragment.subscribe(fragment => {
      // Output: 'tag'
      console.log('Fragment: ', fragment);
    });
    this.router.queryParamMap.subscribe(params => {
      /**
       * output: 'value'
       */
      console.log('Data: ', params);
    });
  }

Answer 6

  initializeComponent() {
    // Example https://example.com?param=value#tag
    this.router.fragment.subscribe(fragment => {
      // Output: 'tag'
      console.log('Fragment: ', fragment);
    });
    this.router.queryParamMap.subscribe(params => {
      /**
       * output: 'value'
       */
      console.log('Data: ', params);
    });
  }

Answer 7

Answer №4

It appears that the issue lies in your variables 'a' and 'b' being marked as PRIVATE. To make them accessible in your HTML, you need to change them to PUBLIC like so:

import { ActivatedRoute, Router } from '@angular/router';
...
export class MyComponent implements OnInit,OnDestroy {
  public a: boolean = true; //<-- PUBLIC
  public b: boolean = true;

  constructor(route: ActivatedRoute)  {
  ...

  ngOnInit(): void {    
    this.route.queryParams.subscribe((queryParams:any) => {
      this.a = queryParams.a;
      this.b = queryParams.b;
     });

Answer 8

It appears that the issue lies in your variables 'a' and 'b' being marked as PRIVATE. To make them accessible in your HTML, you need to change them to PUBLIC like so:

import { ActivatedRoute, Router } from '@angular/router';
...
export class MyComponent implements OnInit,OnDestroy {
  public a: boolean = true; //<-- PUBLIC
  public b: boolean = true;

  constructor(route: ActivatedRoute)  {
  ...

  ngOnInit(): void {    
    this.route.queryParams.subscribe((queryParams:any) => {
      this.a = queryParams.a;
      this.b = queryParams.b;
     });

Answer 9

Answer №5

Don't lose track of 'this'. Make sure to create a function and bind it to this component, then add it to the subscribe callback. You can also save your current context using const self = this

Answer 10

Don't lose track of 'this'. Make sure to create a function and bind it to this component, then add it to the subscribe callback. You can also save your current context using const self = this

Exploring Angular: Embracing the Power of Query String Parameters

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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