Mongoose: Running Scheduled Job Query by Date - node.js

Question

I want to create a scheduled job for patients in a hospital. The patients will be informed every month by their reg_date.
I'm using new Date().getDate() inside my scheduled Jobs to run at 8.00 AM in the morning to send SMS to my patients. Meanwhile, I had been using string format date to save reg_date in my mongoDB. Here is snippets of my mongoDB docs :
{
customer: "John",
reg_date: "2017-02-17T16:39:26.969Z"
}
I've ben surfing for solutions but it turns out nothing, so I decided to post myself. Here is what i am trying to do :
customer.find({"reg_date.getDate()" : new Date(2017, 03, 17).getDate()})
.then(function(data) {
for (var key in data.length) {
sendTheSMS(key[data]);
};
});
E.g: What I am doing is "I want to get every patient who register at 17th day of the month and send them a SMS".
Any help will be appreciated. :D

Answer 1

For this type of bit complex query you need to use aggregation method instead regular find method.
$project this will help you to project your fields, here we are creating a new temporary field day with only date of the reg_date. Then we query using the new field day and we get the result.
This temp field day will never added to your schema or model, it is just like temp view we are creating like in SQL.
Here i projected only customer and day but Please project all the fields necessary in the result.
function getCustomerList(day, callback){
customer.aggregate([
{
$project:{
"customer": "$customer", //repeat the same for all field you want in result
"reg_date": "$reg_date",
"day":{$dayOfMonth:"$reg_date"} //put day of month in 'day'
}
},
{
$match:{
"day": day //now match the day with the incoming day value
}
},
], function(err, result){
callback(err, result);
})
}
getCustomerList(17, function(err, result){ // call the function like this with date you want
// Process the err & result here
});
Result will be like this
[{
"_id" : ObjectId("571f2da8ca97eb10163e6e17"),
"customer" : "John",
"reg_date" : ISODate("2016-04-17T08:58:16.414Z"),
"day" : 17
},
{
"_id" : ObjectId("571f2da8ca97eb10163e6e17"),
"customer" : "Prasanth",
"reg_date" : ISODate("2016-04-17T08:58:16.414Z"),
"day" : 17
}]
Ignore the day field projected during your process...

Answer 2

With reg_date in string you can't query for day of month as it only works with ISODate. I suggest first you convert the string in reg_date in all your documents with a script.
Then the following query should work
customer.aggregate([
{
$project:{
"document": "$$ROOT", //to get the whole document
"day":{$dayOfMonth:"$date"} //put day of month in 'day'
}
},
{
$match:{
"day": 17 //match 17
}
},
], function(data) {
for (var key in data.length) {
sendTheSMS(key[data]);
};
})

Answer 3

Use greater than and less than
var previousDate =new Date(2017, 1, 16); //month starts with 0
var nextDate=new Date(2017, 1, 18);
customer.find({reg_date : { $gt:previousDate,$lt:nextDate}})
.then(function(data) {
for (var key in data.length) {
sendTheSMS(key[data]);
};
});

Answer 4

Since reg_date is stored as a string, and not a Date/ISODate, you're limited as to what kind of query you can run (so I concur with the comment in one of the other answers that you should consider converting them to proper ISODate).
Considering that you want to query a date string for entries with a particular day-of-month, you can use a regular expression query:
customer.find({ reg_date : /-17T/ })
Or, dynamically:
let today = new Date();
let dom = ('00' + today.getDate()).slice(-2); // zero-pad day of month
let re = new RegExp('-' + dom + 'T');
customer.find({ reg_date : re })
You should also read this regarding speed optimizations, but still, regex queries aren't very fast.