drf-paginator/cjs/paginators/base-paginator.js

Module for consuming paginated Django REST framework endpoints.

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.BasePaginator = exports.errors = undefined;

var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();

var _lodash = require('lodash');

var _lodash2 = _interopRequireDefault(_lodash);

var _actions = require('../actions');

var actions = _interopRequireWildcard(_actions);

var _paginatorError = require('../paginator-error');

var _paginatorError2 = _interopRequireDefault(_paginatorError);

function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) newObj[key] = obj[key]; } } newObj.default = obj; return newObj; } }

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

var errors = exports.errors = Object.freeze({
  queryHandlerMissing: 'A query handler must be set to generate parameters'
});

var BasePaginator = exports.BasePaginator = function () {
  function BasePaginator(request) {
    var requestOptions = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : null;

    _classCallCheck(this, BasePaginator);

    this._cache = Object.create(null);
    this._page = 0;
    this._request = request;
    this._requestOptions = _lodash2.default.cloneDeep(requestOptions);
    this.queryHandler = null;
  }

  _createClass(BasePaginator, [{
    key: 'current',
    value: function current() {
      return this.fetchPage(this._page);
    }
  }, {
    key: 'next',
    value: function next() {
      return this.fetchPage(++this._page);
    }
  }, {
    key: 'prev',
    value: function prev() {
      return this.fetchPage(--this._page);
    }
  }, {
    key: 'first',
    value: function first() {
      return this.fetchPage(this._page = 1);
    }
  }, {
    key: 'last',
    value: function last() {
      var _this = this;

      var fetchLastPage = function fetchLastPage(pageCount) {
        return _this.fetchPage(_this._page = pageCount);
      };

      return this.fetchPageCount().then(fetchLastPage);
    }
  }, {
    key: 'fetchPage',
    value: function fetchPage(page) {
      var _this2 = this;

      if (this._hasRequest(page)) {
        return this._getRequest(page).then(_lodash2.default.cloneDeep);
      }

      if (!this._isValidPage(page)) {
        return this._rejectPage(page);
      }

      var handleResponse = function handleResponse(response) {
        return _this2._handleResponse(response, page);
      };

      var request = this._sendRequest(page).then(handleResponse);

      this._cacheRequest(page, request);

      return request.then(_lodash2.default.cloneDeep);
    }
  }, {
    key: 'fetchPageCount',
    value: function fetchPageCount() {
      var _this3 = this;

      if (this._pageCount) {
        return Promise.resolve(this._pageCount);
      }

      var setPageCount = function setPageCount(pageCount) {
        _this3._pageCount = pageCount;

        return pageCount;
      };

      return this.fetchPage(1).then(actions.inferPageCount).then(setPageCount);
    }
  }, {
    key: 'setQueryHandler',
    value: function setQueryHandler(queryHandler) {
      this.queryHandler = queryHandler;

      return this;
    }
  }, {
    key: 'setQueryParams',
    value: function setQueryParams(queryParams) {
      this.queryHandler.setParams(queryParams);
      this._page = this.queryHandler.resolvePage(queryParams);

      return this;
    }
  }, {
    key: '_isValidPage',
    value: function _isValidPage(page) {
      return page >= 1 && (this._pageCount ? page <= this._pageCount : true);
    }
  }, {
    key: '_rejectPage',
    value: function _rejectPage(page) {
      var message = 'Invalid page "' + page + '".';
      var error = new Error(message);
      error.response = { detail: message };

      return Promise.reject(error);
    }
  }, {
    key: '_sendRequest',
    value: function _sendRequest(page) {
      if (!this.queryHandler) {
        throw new _paginatorError2.default(errors.queryHandlerMissing);
      }

      var requestOptions = _lodash2.default.cloneDeep(this._requestOptions);
      var queryParams = this.queryHandler.makeParams(page);

      return this._request(requestOptions, queryParams);
    }
  }, {
    key: '_cacheRequest',
    value: function _cacheRequest(page, response) {
      this._cache[page] = response;
    }
  }, {
    key: '_getRequest',
    value: function _getRequest(page) {
      return this._cache[page];
    }
  }, {
    key: '_hasRequest',
    value: function _hasRequest(page) {
      return !!this._cache[page];
    }
  }, {
    key: '_handleResponse',
    value: function _handleResponse(response, page) {
      if (this.queryHandler.onResponse) {
        this.queryHandler.onResponse(response, page);
      }

      return response;
    }
  }, {
    key: 'page',
    get: function get() {
      return this._page;
    }
  }]);

  return BasePaginator;
}();

exports.default = BasePaginator;