FluentApiClient.ts

export interface RestApi {
  url(url: string): this

  post(body?: BodyInit | null): Promise<Response>

  get(): Promise<Response>

  auth(value: string): this

  headers(key: string, value: string): this

  getUrl(): string

  params(params: URLSearchParams): this
}

class RestApiClient implements RestApi {
  private readonly baseUrl: string

  private readonly u: string[] = []
  private readonly h: [string, string][] = []
  private p?: URLSearchParams

  constructor(baseUrl: string) {
    this.baseUrl = baseUrl
  }

  private request(method: string, body?: BodyInit | null): Promise<Response> {
    return fetch(this.getUrl(), {
      body,
      method,
      headers: this.h,
    })
  }

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

  get(): Promise<Response> {
    return this.request('GET')
  }

  url(url: string): this {
    this.u.push(url)
    return this
  }

  headers(key: string, value: string): this {
    this.h.push([key, value])
    return this
  }

  auth(value: string): this {
    this.h.push(['Authorization', value])
    return this
  }

  params(params: URLSearchParams): this {
    this.p = params
    return this
  }

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

export default RestApiClient