Observables in ionic 3

How to make HTTP request using Rxjs Observable library

Making HTTP request is a vital operation in a front-end application, now we using a Rxjs Observable library. Observable handle multiple values and promise return in single value. Observable is an ES7 feature, so need to make use an external library.

Observable, manipulate the data being emitted. Operators are Map, Filter, Take, Skip, Debounce. use Observables to handle HTTP request rather than Promises.

Meet the Angular 4 HTTP service

Step:1

import an observable in a service, then observable is used to handle values and then import map function, get appropriate JSON values. and catch function is used to handle the error. 

Step:2

Injectable is used to create services that can be injected into any of other components. then create a function and add observable value and use to get multiple values.

Step:3

To handle an error, when the data are not returned in observable HTTP request, you must catch the error and console the error and give the appropriate solution to solve the error

Step:4

import service in ts page, so you can use all function and variable in service page, get services name and use in your function, subscribe will get all return value and gives the JSON values.