fluentClient.ts

import type { RestApi } from './RestApi'

/**
 * Immutable fluent fetch API
 *
 * @param baseUrl
 * @param urls
 * @param headers
 * @param params
 */
function fluentClient(
  baseUrl: string,
  urls: string[] = [],
  headers: [string, string][] = [],
  params?: URLSearchParams
): RestApi {
  if (!baseUrl) {
    throw new Error('baseUrl should not be empty')
  }

  return {
    post(body?: BodyInit | null): Promise<Response> {
      return fetch(this.getUrl(), {
        method: 'POST',
        body,
        headers,
      })
    },

    get(): Promise<Response> {
      return fetch(this.getUrl(), {
        method: 'GET',
        headers,
      })
    },

    url(url: string): RestApi {
      return fluentClient(
        baseUrl,
        url ? [...urls, url] : [...url],
        [...headers],
        params
      )
    },

    header(key: string, value: string): RestApi {
      return fluentClient(
        baseUrl,
        [...urls],
        [...headers, [key, value]],
        params
      )
    },

    auth(value: string): RestApi {
      return fluentClient(
        baseUrl,
        [...urls],
        [...headers, ['Authorization', value]],
        params
      )
    },

    setParams(params: URLSearchParams): RestApi {
      return fluentClient(baseUrl, [...urls], [...headers], params)
    },

    getUrl(): string {
      return (
        [baseUrl, ...urls].join('/') + (params ? `?${params.toString()}` : '')
      )
    },
  }
}

export default fluentClient