how to pass value from one page to another using ionic code example

Example 1: passing data from one page to another in ionic 4

import { Component, OnInit } from '@angular/core';
import { ActivatedRoute, Router } from '@angular/router';
 
@Component({
  selector: 'app-details',
  templateUrl: './details.page.html',
  styleUrls: ['./details.page.scss'],
})
export class DetailsPage implements OnInit {
 
  data: any;
 
  constructor(private route: ActivatedRoute, private router: Router) {
    this.route.queryParams.subscribe(params => {
      if (params && params.special) {
        this.data = JSON.parse(params.special);
      }
    });
  }
 
}

Example 2: passing data from one page to another in ionic 4

import { Component } from '@angular/core';
import { Router } from '@angular/router';
import { DataService } from '../services/data.service';
 
@Component({
  selector: 'app-home',
  templateUrl: 'home.page.html',
  styleUrls: ['home.page.scss'],
})
export class HomePage {
 
  user = {
    name: 'Simon Grimm',
    website: 'www.ionicacademy.com',
    address: {
      zip: 48149,
      city: 'Muenster',
      country: 'DE'
    },
    interests: [
      'Ionic', 'Angular', 'YouTube', 'Sports'
    ]
  };
 
  constructor(private router: Router, private dataService: DataService) { }
 
  openDetailsWithService() {
    this.dataService.setData(42, this.user);
    this.router.navigateByUrl('/details/42');
  }
}