Mongoose: Remove elements from array of objects in Mongo if condition is met

user_4492372 0
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I have an array of objects that stores the date of an API request along with the JSON values of the request and response. The issue is I don't want this log to get massive. I need to set a max limit or remove entries older than a particular date.

I'm trying to use a mongo / mongoose query to delete elements of an array when the date value of that object is greater than 5 days.

This is the relevant section the mongo model:


      log: [
        {
          select: false,
          date: {
            type: Date,
            default: Date.now,
            select: false
          },
          request: { type: String, select: false },
          response: { type: String, select: false }
        }
      ]

I've tried using updateMany and $pull


    const fiveDaysAgo = moment()
      .subtract(5, 'day')
      .format('YYYY-MM-DD');

    // Ensure log value exists in collection
    // Remove any log entry older than five days
    Collection.updateMany(
      { log: { $exists: true } },
      { $pull: { 'log.$[].date': { $gte: fiveDaysAgo } } }
    ).then(data => console.log(data));

This produces this error:

(node:1957) UnhandledPromiseRejectionWarning: MongoError: Cannot apply $pull to a non-array value

If there was a way to set a max value of entires in the array of objects, and automatically pop the oldest entry off when the new entry is inserted that would also work for me.

mongoose node.js mongodb javascript
1 Answers

Based on your schema log is just an array of documents which contain a field date so if you want to build a condition for that field your update can look like below:

Collection.updateMany(
    { log: { $exists: true } },
    { $pull: { 'log': { date: { $lte: fiveDaysAgo } } } }
    ).then(...)
user_62389770
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