Anil Singh | Code-sample.com

What Are HttpHeaders? The Http Headers is immutable Map and each and every set() returns a new instance and applies the changes with lazy parsing. An immutable set of Http headers, with lazy parsing. HttpHeaders Constructor - constructor ( headers ?: string | { [name: string]: string | string [];}); Imports HttpHeaders from - import { HttpHeaders } from '@angular/common/http' ; HttpHeaders class contains the list of methods - 1.       has() - Checks for existence of header by given name. 2.       get() - Returns the first header that matches given name. 3.       keys() - Returns the names of the headers 4.       getAll() - Returns list of header values for a given name. 5.       append() - Append headers by chaining. 6.       set() -   To set a custom header on the request for a given name ...

HttpModule vs. HttpClientModule - HttpClientModule - The HttpClientModule imported form - import { HttpClientModule } from '@angular/common/http' ; NgModule which provides the HttpClient and associated with components services and the interceptors can be added to the chain behind HttpClient by binding them to the multi-provider for HTTP_INTERCEPTORS. HttpModule – Http deprecate @angular/http in favour of @angular/common/http. HttpModule imported from – import { HttpModule } from '@angular/http' ; They both support HTTP calls but HTTP is the older API and will eventually be deprecated. The new HttpClient service is included in the HttpClientModule that used to initiate HTTP request and responses in angular apps. The HttpClientModule is a replacement of HttpModule. For more detail kindly   refer the link....