Adding value to MongoDB using NodeJS

Question

currently i have data that needs to be inserted to mongodb. The data have been successfully inserted into mongodb, however there is some value that i would like to add to the data and append it into mongodb.

How can i do so? This is my code for inserting data into mongodb

var MongoClient = require('mongodb').MongoClient
    , format = require('util').format;

MongoClient.connect('mongodb://127.0.0.1:27017/test', function(err, db) {
    if(err) throw err;

    var collection = db.collection('test_insert');
    collection.insert({ values:parsestring() }, function(err, docs) {
        collection.count(function(err, count) {
            console.log(format("count = %s", count));
        });
    });

    // Locate all the entries using find
    collection.find().toArray(function(err, results) {
        console.dir(results);
        // Let's close the db
        db.close();
    });
});

// "1,61,54,87,20,12/3/2016,8:39AM" this default value
function parsestring(str="1,30,40,50,20,10/10/2016,10:39AM")
{
    return str.split(",");
}

I would like to add value to the text string.

For example: Machine Unit: 1,

Air Temperature °C: 30,

Water Temperature °C: 40,

Heat Temperature °C: 50,

Room Temperature °C: 20,

Date: 10/10/2016,

Time: 10:39AM

You already got comments on the identical question here: stackoverflow.com/questions/41390018/… It still looks fishy and adding the data to an array or better an object is advisable instead of doing string manipulations. — str
– str, Commented Jan 2, 2017 at 8:49
@str what seems so fishy to you? this is a project that i am suppose to do. What do you recommend me to do then? How can i add data to an array/object? — Marcus
– Marcus, Commented Jan 2, 2017 at 8:52
Doing string concatenation and manipulation in a database that is perfectly capable of storing arrays and objects is fishy. You can $push to an array or $set an object. — str
– str, Commented Jan 2, 2017 at 8:55
actually with ´str.split(",")´ you get an array. So when your input string is always the same, you should be able to match each entry in this array to its corresponding "sensor data". Like @str said - there is no need to store the "label" as a string in the database, but you can write a function that amends the labels to each array entry when you read from the DB. (see also: developer.mozilla.org/de/docs/Web/JavaScript/Reference/… - or developer.mozilla.org/de/docs/Web/JavaScript/Reference/…) — fuma
– fuma, Commented Jan 2, 2017 at 9:58

fuma · Accepted Answer · 2017-01-02 10:42:05Z

Like already mentioned in the comments, you should store your data as objects (or arrays). The line str.split(",") already returns you an array, which you store. In your code you also fetch your data as an Array. When you console.dir() your results, you could map your results.entries to a specific output string if you prefer.

collection.find().toArray(function(err, results) {
    console.dir(results); // <= results.entries
    // Let's close the db
    db.close();
});

See also: https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Array/map & https://developer.mozilla.org/de/docs/Web/JavaScript/Reference/Global_Objects/Array/entries

However, if you want to store objects (e.g. for accessing data via identifier) you could simply do it like:

function parsestring(str="1,30,40,50,20,10/10/2016,10:39AM"){
  var dataArr = str.split(",");
  var dbEntry = {};

  dbEntry.machine = dataArr[0];
  dbEntry.airTemp = dataArr[1];
  dbEntry.waterTemp = dataArr[2];
  dbEntry.heatTemp = dataArr[3];
  dbEntry.roomTemp = dataArr[4];
  dbEntry.date = dataArr[5];
  dbEntry.time = dataArr[6];

  return dbEntry;
}

When returning a simple object from mongoDB, you won't need .toArray()

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