import { HttpParams } from '@angular/common/http';
/**
 * create HttpParams from key value object
 *
 */
export declare const httpParamSerializer: (request: {
    [param: string]: simpleType;
}) => HttpParams;
declare type simpleType = string | string[] | number | number[] | Date | null | undefined | boolean;
/**
 * 复杂类型请使用json, 改用post
 * @example
 *      toQueryString({ a: 2, b: 'abc', c: true, d: false })        -> a=2&b=abc&c=true&d=false
 *      toQueryString({ a: 2, b: new Date() })                      -> yyyy-MM-dd HH:mm:ss
 *      toQueryString({ a: null, b: undefined, c: 1 })              -> a=&b=&c=1
 */
export declare function toQueryString(fromObject: {
    [param: string]: simpleType;
}): string;
export {};