how to call api in time interval in ionic - api

Question

I am working on ionic framework and i want to call API call in some time interval for ex. every 30 seconds, i want to start and stop this API call manually using button or something else. as i am new in ionic framwork i dont know how to achieve that, all i know is to call api, but i don't know how to call API in specific time interval, starting and stopping manually. so can anyone help me? thanks is advance. what i have done till now is below,
authenticate.ts
import { Injectable } from '#angular/core';
import { Http } from '#angular/http';
import 'rxjs/add/operator/map';
#Injectable()
export class AuthenticateProvider {
body: any;
// apiUrl = 'https://jsonplaceholder.typicode.com';
apiUrl = 'http://dev123:5800/api';
getToken(body) {
if (this.body) {
return Promise.resolve(this.body);
}
return new Promise((resolve,reject) => {
this.http.post(this.apiUrl+'/authenticate',body)
.subscribe(res => {
resolve(res);
}, (err) => {
reject(err);
});
});
}
}
login.ts
export class LoginPage {
constructor(public navCtrl: NavController,
public authenticateProvider: AuthenticateProvider) {
}
getToken() {
this.authenticateProvider.getToken(this.creds)
.then(result => {
if (JSON.parse(result.text()).response !== "OK") {
this.err = JSON.parse(result.text()).response;
} else {
dosomething();
}
}, (err) => {
console.log("Error is" + err);
});
}
}

Answer 1

Create the service (I forgot its called provider these days)
ionic g provider interval
The provider code:
//interval.ts
import {Injectable} from '#angular/core';
#Injectable()
export class IntervalProvider {
intervalHandle: any = null;
constructor() {
}
toggleInterval() {
if (this.intervalHandle === null) {
this.intervalHandle = setInterval(() => {
this.callAPI();
}, 1000);
} else {
clearInterval(this.intervalHandle);
this.intervalHandle = null;
}
}
callAPI() {
console.log('API called');
}
}
Injecting and using the provider. The function toggleInterval() I am calling from a button click.
//home.ts
import { Component } from '#angular/core';
import {IntervalProvider} from '../../providers/interval/interval';
#Component({
selector: 'page-home',
templateUrl: 'home.html'
})
export class HomePage {
constructor(private intervalProvider: IntervalProvider) {
}
// called by your click button
toggleInterval() {
this.intervalProvider.toggleInterval();
}
}