import { HttpClient, HttpHeaders, HttpParams } from '@angular/common/http';
import { Observable } from 'rxjs';
import * as i0 from "@angular/core";
/**
 * Http service to fetch the data from and post data to API server.
 * @export
 * @class HttpService
 */
export declare class HttpService {
    private http;
    constructor(http: HttpClient);
    /**
     * Fetches the data from server using http get method.
     * @param {string} url - API endpoint URL.
     * @param {{ key: string; value: string }[]} [headers]
     * @usageNotes headers: { key: string; value: string }[] = [
        { key: 'Access-Control-Allow-Origin', value: '*' },
      ]
     * @param {{ key: string; value: string }[]} [params]
     * @usageNotes params: { key: string; value: string }[] = [
        { key: 'page', value: '2' },
      ];
     * @return {Observable<any>} - returns the response received from server and return type is Observable<any>
     * @memberof HttpService
     */
    getData(url: string, params?: {
        key: string;
        value: string;
    }[], headers?: {
        key: string;
        value: string;
    }[]): Observable<any>;
    /**
     * Post the data to the server using http post method.
     * @param {string} url - API endpoint URL.
     * @param {any} body - the data to be posted to the server as a body content.
     * @param {{ key: string; value: string }[]} [headers]
     * @usageNotes headers: { key: string; value: string }[] = [
        { key: 'Access-Control-Allow-Origin', value: '*' },
       ]
    * @param {{ key: string; value: string }[]} [params]
    * @usageNotes params: { key: string; value: string }[] = [
        { key: 'page', value: '2' },
      ];
    * @return {Observable<any>} - returns the response received from server and return type is Observable<any>
    * @memberof HttpService
    */
    postData(url: string, body: any, headers?: {
        key: string;
        value: string;
    }[], params?: {
        key: string;
        value: string;
    }[]): Observable<any>;
    /**
     * Update the existing data using http put method.
     * @param {string} url - API endpoint URL.
     * @param {any} body - the data to be updated to the server as a body content.
     * @param {{ key: string; value: string }[]} [headers]
     * @usageNotes headers: { key: string; value: string }[] = [
        { key: 'Access-Control-Allow-Origin', value: '*' },
      ]
     * @param {{ key: string; value: string }[]} [params]
     * @usageNotes params: { key: string; value: string }[] = [
        { key: 'page', value: '2' },
      ];
     * @return {Observable<any>} - returns the response received from server and return type is Observable<any>
     * @memberof HttpService
     */
    putData(url: string, body: any, headers?: {
        key: string;
        value: string;
    }[], params?: {
        key: string;
        value: string;
    }[]): Observable<any>;
    /**
     * Delete the data from server using http delete method.
     * @param {string} url - API endpoint URL.
     * @param body - the data to be deleted from the server as a body content.
     * @param {{ key: string; value: string }[]} [headers]
     * @usageNotes headers: { key: string; value: string }[] = [
        { key: 'Access-Control-Allow-Origin', value: '*' },
      ]
     * @param {{ key: string; value: string }[]} [params]
      @ @usageNotes params: { key: string; value: string }[] = [
        { key: 'page', value: '2' },
      ];
     * @return {Observable<any>} - returns the response received from server and return type is Observable<any>
     * @memberof HttpService
     */
    deleteData(url: string, body?: any, headers?: {
        key: string;
        value: string;
    }[], params?: {
        key: string;
        value: string;
    }[]): Observable<any>;
    /**
     * Post FormData (multipart) to the server using http post method.
     * Does NOT set Content-Type header so the browser can set the correct multipart boundary.
     * @param {string} url - API endpoint URL.
     * @param {FormData} formData - the FormData payload.
     * @param {{ key: string; value: string }[]} [headers]
     * @param {{ key: string; value: string }[]} [params]
     * @return {Observable<any>}
     * @memberof HttpService
     */
    postFormData(url: string, formData: FormData, headers?: {
        key: string;
        value: string;
    }[], params?: {
        key: string;
        value: string;
    }[]): Observable<any>;
    /**
     * Utility method to construct the headers that will be passed to the API requests.
     * @param {({ key: string; value: string }[])} headers - Http headers that will be constructed and passed along with the API requests.
     * @usageNotes headers: { key: string; value: string }[] = [
        { key: 'Access-Control-Allow-Origin', value: '*' },
       ]
     * @return {HttpHeaders} - returns constructed http headers.
     * @memberof HttpService
     */
    getHeaders(headers: {
        key: string;
        value: string;
    }[]): HttpHeaders;
    /**
     * Utility method to construct the params that will be passed to the API requests.
     * @param {({ key: string; value: string }[])} params - Http headers that will be constructed and passed along with the API requests.
     * @usageNotes params: { key: string; value: string }[] = [
        { key: 'page', value: '2' },
      ];
     * @return {HttpParams} - returns constructed http params.
     * @memberof HttpService
     */
    getParams(params: {
        key: string;
        value: string;
    }[]): HttpParams;
    static ɵfac: i0.ɵɵFactoryDeclaration<HttpService, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<HttpService>;
}