lib6/record.js

/**
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [https://neo4j.com]
 *
 * 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.
 */
import { newError } from './error';
function generateFieldLookup(keys) {
    const lookup = {};
    keys.forEach((name, idx) => {
        lookup[name] = idx;
    });
    return lookup;
}
/**
 * Records make up the contents of the {@link Result}, and is how you access
 * the output of a query. A simple query might yield a result stream
 * with a single record, for instance:
 *
 *     MATCH (u:User) RETURN u.name, u.age
 *
 * This returns a stream of records with two fields, named `u.name` and `u.age`,
 * each record represents one user found by the query above. You can access
 * the values of each field either by name:
 *
 *     record.get("u.name")
 *
 * Or by it's position:
 *
 *     record.get(0)
 *
 * @access public
 */
class Record {
    /**
     * Create a new record object.
     * @constructor
     * @protected
     * @param {string[]} keys An array of field keys, in the order the fields appear in the record
     * @param {Array} fields An array of field values
     * @param {Object} fieldLookup An object of fieldName -> value index, used to map
     *                            field names to values. If this is null, one will be
     *                            generated.
     */
    constructor(keys, fields, fieldLookup) {
        /**
         * Field keys, in the order the fields appear in the record.
         * @type {string[]}
         */
        this.keys = keys;
        /**
         * Number of fields
         * @type {Number}
         */
        this.length = keys.length;
        this._fields = fields;
        this._fieldLookup = fieldLookup !== null && fieldLookup !== void 0 ? fieldLookup : generateFieldLookup(keys);
    }
    /**
     * Run the given function for each field in this record. The function
     * will get three arguments - the value, the key and this record, in that
     * order.
     *
     * @param {function(value: Object, key: string, record: Record)} visitor the function to apply to each field.
     * @returns {void} Nothing
     */
    forEach(visitor) {
        for (const [key, value] of this.entries()) {
            visitor(value, key, this);
        }
    }
    /**
     * Run the given function for each field in this record. The function
     * will get three arguments - the value, the key and this record, in that
     * order.
     *
     * @param {function(value: Object, key: string, record: Record)} visitor the function to apply on each field
     * and return a value that is saved to the returned Array.
     *
     * @returns {Array}
     */
    map(visitor) {
        const resultArray = [];
        for (const [key, value] of this.entries()) {
            resultArray.push(visitor(value, key, this));
        }
        return resultArray;
    }
    /**
     * Iterate over results. Each iteration will yield an array
     * of exactly two items - the key, and the value (in order).
     *
     * @generator
     * @returns {IterableIterator<Array>}
     */
    *entries() {
        for (let i = 0; i < this.keys.length; i++) {
            yield [this.keys[i], this._fields[i]];
        }
    }
    /**
     * Iterate over values.
     *
     * @generator
     * @returns {IterableIterator<Object>}
     */
    *values() {
        for (let i = 0; i < this.keys.length; i++) {
            yield this._fields[i];
        }
    }
    /**
     * Iterate over values. Delegates to {@link Record#values}
     *
     * @generator
     * @returns {IterableIterator<Object>}
     */
    *[Symbol.iterator]() {
        for (let i = 0; i < this.keys.length; i++) {
            yield this._fields[i];
        }
    }
    /**
     * Generates an object out of the current Record
     *
     * @returns {Object}
     */
    toObject() {
        // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
        const obj = {};
        for (const [key, value] of this.entries()) {
            obj[key] = value;
        }
        return obj;
    }
    /**
     * Get a value from this record, either by index or by field key.
     *
     * @param {string|Number} key Field key, or the index of the field.
     * @returns {*}
     */
    get(key) {
        let index;
        if (!(typeof key === 'number')) {
            index = this._fieldLookup[key];
            if (index === undefined) {
                throw newError(`This record has no field with key '${key.toString()}', available keys are: [` +
                    this.keys.toString() +
                    '].');
            }
        }
        else {
            index = key;
        }
        if (index > this._fields.length - 1 || index < 0) {
            throw newError("This record has no field with index '" +
                index.toString() +
                "'. Remember that indexes start at `0`, " +
                'and make sure your query returns records in the shape you meant it to.');
        }
        return this._fields[index];
    }
    /**
     * Check if a value from this record, either by index or by field key, exists.
     *
     * @param {string|Number} key Field key, or the index of the field.
     * @returns {boolean}
     */
    has(key) {
        // if key is a number, we check if it is in the _fields array
        if (typeof key === 'number') {
            return key >= 0 && key < this._fields.length;
        }
        // if it's not a number, we check _fieldLookup dictionary directly
        return this._fieldLookup[key] !== undefined;
    }
}
export default Record;