Node JS version

node_modules/cassandra-driver/lib/mapping/result.js

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+/*
+ * Copyright DataStax, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const util = require('util');
+const utils = require('../utils');
+const inspectMethod = util.inspect.custom || 'inspect';
+
+/**
+ * Represents the result of an execution as an iterable of objects in the Mapper.
+ * @alias module:mapping~Result
+ */
+class Result {
+  /**
+   * Creates a new instance of Result.
+   * @param {ResultSet} rs
+   * @param {ModelMappingInfo} info
+   * @param {Function} rowAdapter
+   */
+  constructor(rs, info, rowAdapter) {
+    this._rs = rs;
+    this._info = info;
+    this._rowAdapter = rowAdapter;
+
+    /**
+     * When there is a single cell containing the result of the a LWT operation, hide the result from the user.
+     * @private
+     */
+    this._isEmptyLwt = (rs.columns !== null
+      && rs.columns.length === 1 && this._rs.rowLength === 1 && rs.columns[0].name === '[applied]');
+
+    /**
+     * Gets the amount of the documents contained in this Result instance.
+     * <p>
+     *   When the results are paged, it returns the length of the current paged results not the total amount of
+     *   rows in the table matching the query.
+     * </p>
+     * @type {Number}
+     */
+    this.length = this._isEmptyLwt ? 0 : (rs.rowLength || 0);
+
+    /**
+     * A string token representing the current page state of query.
+     * <p>
+     *   When provided, it can be used in the following executions to continue paging and retrieve the remained of the
+     *   result for the query.
+     * </p>
+     * @type {String}
+     * @default null
+     */
+    this.pageState = rs.pageState;
+  }
+
+  /**
+   * When this instance is the result of a conditional update query, it returns whether it was successful.
+   * Otherwise, it returns <code>true</code>.
+   * <p>
+   *   For consistency, this method always returns <code>true</code> for non-conditional queries (although there is
+   *   no reason to call the method in that case). This is also the case for conditional DDL statements
+   *   (CREATE KEYSPACE... IF NOT EXISTS, CREATE TABLE... IF NOT EXISTS), for which the server doesn't return
+   *   information whether it was applied or not.
+   * </p>
+   */
+  wasApplied() {
+    return this._rs.wasApplied();
+  }
+
+  /**
+   * Gets the first document in this result or null when the result is empty.
+   */
+  first() {
+    if (!this._rs.rowLength || this._isEmptyLwt) {
+      return null;
+    }
+    return this._rowAdapter(this._rs.rows[0], this._info);
+  }
+
+  /**
+   * Returns a new Iterator object that contains the document values.
+   */
+  *[Symbol.iterator]() {
+    if (this._isEmptyLwt) {
+      // Empty iterator
+      return;
+    }
+
+    for (let i = 0; i < this._rs.rows.length; i++) {
+      yield this._rowAdapter(this._rs.rows[i], this._info);
+    }
+  }
+
+  /**
+   * Converts the current instance to an Array of documents.
+   * @return {Array<Object>}
+   */
+  toArray() {
+    if (this._isEmptyLwt || !this._rs.rows) {
+      return utils.emptyArray;
+    }
+
+    return this._rs.rows.map(row => this._rowAdapter(row, this._info));
+  }
+
+  /**
+   * Executes a provided function once per result element.
+   * @param {Function} callback Function to execute for each element, taking two arguments: currentValue and index.
+   * @param {Object} [thisArg] Value to use as <code>this</code> when executing callback.
+   */
+  forEach(callback, thisArg) {
+    let index = 0;
+    thisArg = thisArg || this;
+    for (const doc of this) {
+      callback.call(thisArg, doc, index++);
+    }
+  }
+
+  [inspectMethod]() {
+    return this.toArray();
+  }
+}
+
+module.exports = Result;