index.js

// Copyright (c) 2016-2021 Memgraph Ltd. [https://memgraph.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.

const Bindings = require('bindings')('nodemgclient');
const pjson = require('./package.json');

// The purpose of create functions is to simplify creation of Memgraph specific
// data types, e.g. temporal types.

/**
  * Create Memgraph compatible date object.
  * @param {number} days - The number of days since 1970-01-01 (Unix epoch).
  */
function createMgDate(days) {
  return {
    "objectType": "date",
    "days": days,
  }
}

/**
  * Create Memgraph compatible local time object.
  * @param {number} nanoseconds - The number of nanoseconds since midnight.
  */
function createMgLocalTime(nanoseconds) {
  return {
    "objectType": "local_time",
    "nanoseconds": nanoseconds,
  }
}

/**
  * Create Memgraph compatible local date time object.
  * @param {number} seconds - The number of seconds since 1970-01-01T00:00:00
  * (Unix epoch).
  * @param {number} nanoseconds - The number of nanoseconds since the last
  * second.
  */
function createMgLocalDateTime(seconds, nanoseconds) {
  return {
    "objectType": "local_date_time",
    "seconds": seconds,
    "nanoseconds": nanoseconds,
  }
}

/**
  * Create Memgraph compatible duration object.
  * NOTE: Semantically Memgraph duration is a sum of all
  * components (days, seconds, nanoseconds).
  * @param {number} days - The number of days.
  * @param {number} seconds - The number of seconds.
  * @param {number} nanoseconds - The number of nanoseconds.
  */
function createMgDuration(days, seconds, nanoseconds) {
  return {
    "objectType": "duration",
    "days": days,
    "seconds": seconds,
    "nanoseconds": nanoseconds,
  }
}

// This class exists becuase of additional logic that is easier to implement in
// JavaScript + to extend the implementation with easy to use primitives.
class Connection {
  constructor(client) {
    this.client = client;
  }

  async Execute(query, params={}) {
    return await this.client.Execute(query, params);
  }

  async FetchAll() {
    return await this.client.FetchAll();
  }

  async DiscardAll() {
    return await this.client.DiscardAll();
  }

  async Begin() {
    return await this.client.Begin();
  }

  async Commit() {
    return await this.client.Commit();
  }

  async Rollback() {
    return await this.client.Rollback();
  }

  async ExecuteAndFetchAll(query, params={}) {
    await this.client.Execute(query, params);
    return await this.client.FetchAll();
  }
}

const Memgraph = {
  Client: () => {
    return new Bindings.Client("nodemgclient/" + pjson.version);
  },
  Connect: async (params) => {
    let client = new Bindings.Client("nodemgclient/" + pjson.version);
    // TODO(gitbuda): If the second client is not passed, execution blocks, check why.
    client = await client.Connect(params);
    return new Connection(client);
  }
}

module.exports = {
  Connection,
  default: Memgraph,
  Client: Memgraph.Client,
  Connect: Memgraph.Connect,
  Memgraph: Memgraph,
  createMgDate: createMgDate,
  createMgLocalTime: createMgLocalTime,
  createMgLocalDateTime: createMgLocalDateTime,
  createMgDuration: createMgDuration,
}