code: function processTerm (handler, obj = {}, isDefault) {
    let req = {
      term: this._request.term.then(value => {
        assignRequest(req, this._request, obj)
        if (this._request.error && !isDefault) return null
        if (isDefault) req.error = null
        return handler(value, req)
      })
    }
    return new v(this._client, req)
  }
docs: processes the current term promise and updates the context
  @param handler
  @param obj
  @return {v}