var util = require('./util'); /** * DataSet * * Usage: * var dataSet = new DataSet({ * fieldId: '_id', * type: { * // ... * } * }); * * dataSet.add(item); * dataSet.add(data); * dataSet.update(item); * dataSet.update(data); * dataSet.remove(id); * dataSet.remove(ids); * var data = dataSet.get(); * var data = dataSet.get(id); * var data = dataSet.get(ids); * var data = dataSet.get(ids, options, data); * dataSet.clear(); * * A data set can: * - add/remove/update data * - gives triggers upon changes in the data * - can import/export data in various data formats * * @param {Array | DataTable} [data] Optional array with initial data * @param {Object} [options] Available options: * {String} fieldId Field name of the id in the * items, 'id' by default. * {Object.} [type] * {String[]} [fields] field names to be returned * {function} [filter] filter items * {String | function} [order] Order the items by * a field name or custom sort function. * {Array | DataTable} [data] If provided, items will be appended to this * array or table. Required in case of Google * DataTable. * * @throws Error */ DataSet.prototype.get = function (args) { var me = this; // parse the arguments var id, ids, options, data; var firstType = util.getType(arguments[0]); if (firstType == 'String' || firstType == 'Number') { // get(id [, options] [, data]) id = arguments[0]; options = arguments[1]; data = arguments[2]; } else if (firstType == 'Array') { // get(ids [, options] [, data]) ids = arguments[0]; options = arguments[1]; data = arguments[2]; } else { // get([, options] [, data]) options = arguments[0]; data = arguments[1]; } // determine the return type var returnType; if (options && options.returnType) { var allowedValues = ["DataTable", "Array", "Object"]; returnType = allowedValues.indexOf(options.returnType) == -1 ? "Array" : options.returnType; if (data && (returnType != util.getType(data))) { throw new Error('Type of parameter "data" (' + util.getType(data) + ') ' + 'does not correspond with specified options.type (' + options.type + ')'); } if (returnType == 'DataTable' && !util.isDataTable(data)) { throw new Error('Parameter "data" must be a DataTable ' + 'when options.type is "DataTable"'); } } else if (data) { returnType = (util.getType(data) == 'DataTable') ? 'DataTable' : 'Array'; } else { returnType = 'Array'; } // build options var type = options && options.type || this._options.type; var filter = options && options.filter; var items = [], item, itemId, i, len; // convert items if (id != undefined) { // return a single item item = me._getItem(id, type); if (filter && !filter(item)) { item = null; } } else if (ids != undefined) { // return a subset of items for (i = 0, len = ids.length; i < len; i++) { item = me._getItem(ids[i], type); if (!filter || filter(item)) { items.push(item); } } } else { // return all items for (itemId in this._data) { if (this._data.hasOwnProperty(itemId)) { item = me._getItem(itemId, type); if (!filter || filter(item)) { items.push(item); } } } } // order the results if (options && options.order && id == undefined) { this._sort(items, options.order); } // filter fields of the items if (options && options.fields) { var fields = options.fields; if (id != undefined) { item = this._filterFields(item, fields); } else { for (i = 0, len = items.length; i < len; i++) { items[i] = this._filterFields(items[i], fields); } } } // return the results if (returnType == 'DataTable') { var columns = this._getColumnNames(data); if (id != undefined) { // append a single item to the data table me._appendRow(data, columns, item); } else { // copy the items to the provided data table for (i = 0; i < items.length; i++) { me._appendRow(data, columns, items[i]); } } return data; } else if (returnType == "Object") { var result = {}; for (i = 0; i < items.length; i++) { result[items[i].id] = items[i]; } return result; } else { // return an array if (id != undefined) { // a single item return item; } else { // multiple items if (data) { // copy the items to the provided array for (i = 0, len = items.length; i < len; i++) { data.push(items[i]); } return data; } else { // just return our array return items; } } } }; /** * Get ids of all items or from a filtered set of items. * @param {Object} [options] An Object with options. Available options: * {function} [filter] filter items * {String | function} [order] Order the items by * a field name or custom sort function. * @return {Array} ids */ DataSet.prototype.getIds = function (options) { var data = this._data, filter = options && options.filter, order = options && options.order, type = options && options.type || this._options.type, i, len, id, item, items, ids = []; if (filter) { // get filtered items if (order) { // create ordered list items = []; for (id in data) { if (data.hasOwnProperty(id)) { item = this._getItem(id, type); if (filter(item)) { items.push(item); } } } this._sort(items, order); for (i = 0, len = items.length; i < len; i++) { ids[i] = items[i][this._fieldId]; } } else { // create unordered list for (id in data) { if (data.hasOwnProperty(id)) { item = this._getItem(id, type); if (filter(item)) { ids.push(item[this._fieldId]); } } } } } else { // get all items if (order) { // create an ordered list items = []; for (id in data) { if (data.hasOwnProperty(id)) { items.push(data[id]); } } this._sort(items, order); for (i = 0, len = items.length; i < len; i++) { ids[i] = items[i][this._fieldId]; } } else { // create unordered list for (id in data) { if (data.hasOwnProperty(id)) { item = data[id]; ids.push(item[this._fieldId]); } } } } return ids; }; /** * Returns the DataSet itself. Is overwritten for example by the DataView, * which returns the DataSet it is connected to instead. */ DataSet.prototype.getDataSet = function () { return this; }; /** * Execute a callback function for every item in the dataset. * @param {function} callback * @param {Object} [options] Available options: * {Object.} [type] * {String[]} [fields] filter fields * {function} [filter] filter items * {String | function} [order] Order the items by * a field name or custom sort function. */ DataSet.prototype.forEach = function (callback, options) { var filter = options && options.filter, type = options && options.type || this._options.type, data = this._data, item, id; if (options && options.order) { // execute forEach on ordered list var items = this.get(options); for (var i = 0, len = items.length; i < len; i++) { item = items[i]; id = item[this._fieldId]; callback(item, id); } } else { // unordered for (id in data) { if (data.hasOwnProperty(id)) { item = this._getItem(id, type); if (!filter || filter(item)) { callback(item, id); } } } } }; /** * Map every item in the dataset. * @param {function} callback * @param {Object} [options] Available options: * {Object.} [type] * {String[]} [fields] filter fields * {function} [filter] filter items * {String | function} [order] Order the items by * a field name or custom sort function. * @return {Object[]} mappedItems */ DataSet.prototype.map = function (callback, options) { var filter = options && options.filter, type = options && options.type || this._options.type, mappedItems = [], data = this._data, item; // convert and filter items for (var id in data) { if (data.hasOwnProperty(id)) { item = this._getItem(id, type); if (!filter || filter(item)) { mappedItems.push(callback(item, id)); } } } // order items if (options && options.order) { this._sort(mappedItems, options.order); } return mappedItems; }; /** * Filter the fields of an item * @param {Object} item * @param {String[]} fields Field names * @return {Object} filteredItem * @private */ DataSet.prototype._filterFields = function (item, fields) { var filteredItem = {}; for (var field in item) { if (item.hasOwnProperty(field) && (fields.indexOf(field) != -1)) { filteredItem[field] = item[field]; } } return filteredItem; }; /** * Sort the provided array with items * @param {Object[]} items * @param {String | function} order A field name or custom sort function. * @private */ DataSet.prototype._sort = function (items, order) { if (util.isString(order)) { // order by provided field name var name = order; // field name items.sort(function (a, b) { var av = a[name]; var bv = b[name]; return (av > bv) ? 1 : ((av < bv) ? -1 : 0); }); } else if (typeof order === 'function') { // order by sort function items.sort(order); } // TODO: extend order by an Object {field:String, direction:String} // where direction can be 'asc' or 'desc' else { throw new TypeError('Order must be a function or a string'); } }; /** * Remove an object by pointer or by id * @param {String | Number | Object | Array} id Object or id, or an array with * objects or ids to be removed * @param {String} [senderId] Optional sender id * @return {Array} removedIds */ DataSet.prototype.remove = function (id, senderId) { var removedIds = [], i, len, removedId; if (Array.isArray(id)) { for (i = 0, len = id.length; i < len; i++) { removedId = this._remove(id[i]); if (removedId != null) { removedIds.push(removedId); } } } else { removedId = this._remove(id); if (removedId != null) { removedIds.push(removedId); } } if (removedIds.length) { this._trigger('remove', {items: removedIds}, senderId); } return removedIds; }; /** * Remove an item by its id * @param {Number | String | Object} id id or item * @returns {Number | String | null} id * @private */ DataSet.prototype._remove = function (id) { if (util.isNumber(id) || util.isString(id)) { if (this._data[id]) { delete this._data[id]; return id; } } else if (id instanceof Object) { var itemId = id[this._fieldId]; if (itemId && this._data[itemId]) { delete this._data[itemId]; return itemId; } } return null; }; /** * Clear the data * @param {String} [senderId] Optional sender id * @return {Array} removedIds The ids of all removed items */ DataSet.prototype.clear = function (senderId) { var ids = Object.keys(this._data); this._data = {}; this._trigger('remove', {items: ids}, senderId); return ids; }; /** * Find the item with maximum value of a specified field * @param {String} field * @return {Object | null} item Item containing max value, or null if no items */ DataSet.prototype.max = function (field) { var data = this._data, max = null, maxField = null; for (var id in data) { if (data.hasOwnProperty(id)) { var item = data[id]; var itemField = item[field]; if (itemField != null && (!max || itemField > maxField)) { max = item; maxField = itemField; } } } return max; }; /** * Find the item with minimum value of a specified field * @param {String} field * @return {Object | null} item Item containing max value, or null if no items */ DataSet.prototype.min = function (field) { var data = this._data, min = null, minField = null; for (var id in data) { if (data.hasOwnProperty(id)) { var item = data[id]; var itemField = item[field]; if (itemField != null && (!min || itemField < minField)) { min = item; minField = itemField; } } } return min; }; /** * Find all distinct values of a specified field * @param {String} field * @return {Array} values Array containing all distinct values. If data items * do not contain the specified field are ignored. * The returned array is unordered. */ DataSet.prototype.distinct = function (field) { var data = this._data; var values = []; var fieldType = this._options.type && this._options.type[field] || null; var count = 0; var i; for (var prop in data) { if (data.hasOwnProperty(prop)) { var item = data[prop]; var value = item[field]; var exists = false; for (i = 0; i < count; i++) { if (values[i] == value) { exists = true; break; } } if (!exists && (value !== undefined)) { values[count] = value; count++; } } } if (fieldType) { for (i = 0; i < values.length; i++) { values[i] = util.convert(values[i], fieldType); } } return values; }; /** * Add a single item. Will fail when an item with the same id already exists. * @param {Object} item * @return {String} id * @private */ DataSet.prototype._addItem = function (item) { var id = item[this._fieldId]; if (id != undefined) { // check whether this id is already taken if (this._data[id]) { // item already exists throw new Error('Cannot add item: item with id ' + id + ' already exists'); } } else { // generate an id id = util.randomUUID(); item[this._fieldId] = id; } var d = {}; for (var field in item) { if (item.hasOwnProperty(field)) { var fieldType = this._type[field]; // type may be undefined d[field] = util.convert(item[field], fieldType); } } this._data[id] = d; return id; }; /** * Get an item. Fields can be converted to a specific type * @param {String} id * @param {Object.} [types] field types to convert * @return {Object | null} item * @private */ DataSet.prototype._getItem = function (id, types) { var field, value; // get the item from the dataset var raw = this._data[id]; if (!raw) { return null; } // convert the items field types var converted = {}; if (types) { for (field in raw) { if (raw.hasOwnProperty(field)) { value = raw[field]; converted[field] = util.convert(value, types[field]); } } } else { // no field types specified, no converting needed for (field in raw) { if (raw.hasOwnProperty(field)) { value = raw[field]; converted[field] = value; } } } return converted; }; /** * Update a single item: merge with existing item. * Will fail when the item has no id, or when there does not exist an item * with the same id. * @param {Object} item * @return {String} id * @private */ DataSet.prototype._updateItem = function (item) { var id = item[this._fieldId]; if (id == undefined) { throw new Error('Cannot update item: item has no id (item: ' + JSON.stringify(item) + ')'); } var d = this._data[id]; if (!d) { // item doesn't exist throw new Error('Cannot update item: no item with id ' + id + ' found'); } // merge with current item for (var field in item) { if (item.hasOwnProperty(field)) { var fieldType = this._type[field]; // type may be undefined d[field] = util.convert(item[field], fieldType); } } return id; }; /** * Get an array with the column names of a Google DataTable * @param {DataTable} dataTable * @return {String[]} columnNames * @private */ DataSet.prototype._getColumnNames = function (dataTable) { var columns = []; for (var col = 0, cols = dataTable.getNumberOfColumns(); col < cols; col++) { columns[col] = dataTable.getColumnId(col) || dataTable.getColumnLabel(col); } return columns; }; /** * Append an item as a row to the dataTable * @param dataTable * @param columns * @param item * @private */ DataSet.prototype._appendRow = function (dataTable, columns, item) { var row = dataTable.addRow(); for (var col = 0, cols = columns.length; col < cols; col++) { var field = columns[col]; dataTable.setValue(row, col, item[field]); } }; module.exports = DataSet;