ES6 fetch helper for couch

couch.js

couch = (uri, opts = {body: null, params: {include_docs: true}}) =>
  fetch(uri.concat('?', Object.entries(opts.params).map(ary =>
    ary.map(encodeURIComponent).join('=')).join('&')),
    Object.assign({
      ...(opts.body && { body: JSON.stringify(opts.body) })
      , headers: {
        'Accept': 'application/json'
        , 'Content-Type': 'application/json'
      }
      , method: 'GET'
    }, opts)).
      then(resp => resp.ok ? resp.json() : Promise.reject(resp.statusText)).
      then(json => json.error ? Promise.reject(json.error) : json).
      then(json => json.rows ? json.rows.map(r => r.doc ? r.doc : r.value) :
        json).
      catch(console.debug)