Is it possible to update a document from a post save mongoose middleware? Because it is not working for me.

I have tried in different ways.

Way 1:

QuoteSchema.post('save', function(doc) {
if (doc.quoteString) {
    return;
}
this.quoteString = doc.quoteNumber + "";
this._doc.quoteString = doc.quoteNumber + "";
// update the record with quoteString 
this.update({ _id: this.id }, this, { new: true }, function(err, result) {
    if (!err) {
        console.log("Document Updated");
    }
});
    console.log('post save', doc.quoteString);
});

Way 2: because this contains the saved object id so I tried directly.

QuoteSchema.post('save', function(doc) {
if (doc.quoteString) {
    return;
}
this.quoteString = doc.quoteNumber + "";
this._doc.quoteString = doc.quoteNumber + "";
enter code here
// update the record with quoteString 
this.update(function(err) {
    if (!err) {
        console.log("Document Updated");
    }
});
    console.log('post save', doc.quoteString);
});

Way 3:

QuoteSchema.post('save', function(doc) {
if (doc.quoteString) {
    return;
}
var _quoteString = doc.quoteNumber+"";

this.update({ _id: doc._id }, { $set: { "quoteString": _quoteString } }, function(err) {
    if (!err) {
        console.log("Document Updated");
    }
});
console.log('post save', doc.quoteString);
});

None of these ways works for me.

All I have to do is to update QuoteNumber field after the save. QuoteNumber is being generated from mongoose autoincrement which requires a number field. and I'm also saving a string version of quoteNumber in quoteString field so that in the UI, I can perform regex search in an autocomplete. As regular expression does not work with number type.

any suggestions will be helpful. Thanks.

Just make the autoincrementing field virtual and you don't have to worry about post save hook...

const QuoteSchema = new Schema(
  {
    quoteNumber: { type: Number },
    quoteString: { type: String },
  },
);

QuoteSchema.virtual('quote').set(function(value) {
  this.quoteNumber = Number(value);
  this.quoteString = String(value);
});

QuoteSchema.virtual('quote').get(function() {
  return this.quoteNumber;
});

Setup:

QuoteSchema.plugin(autoIncrement.plugin, { model: 'Quote', field: 'quote' });