How to create mongoose schema dynamically?

Question

I have an app that works on node.js with MongoDB and mongoose. My app simply sends/deletes/edits form data and for that, I have such mongoose model:

var mongoose = require('mongoose');

module.exports = mongoose.model('appForm', {
    User_id : {type: String},
    LogTime : {type: String},
    feeds : [   
    {
        Name: {type: String},
        Text : {type: String},
    }
    ]
});

and that works just fine!

Now, I would like to add a function to the form so that the user can add a field(or fields) to form and enter a text in it and post it. Creating that dynamic functionality on the client side is no problem but I understand that my mongoose.model has to be correctly structured. My question is: how do I add that variable values(dynamically created form data name and its text) to mongoose schema?

I see that using strict: false and Schema.Types.Mixed is advised. however, I can't figure out... What I have tried:

var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var feedSchema = new Schema({strict:false});

module.exports = mongoose.model('appForm', feedSchema);

Any tips? Thanks in advance!

Carlie

Answer 1

Apply the strict: false option to your existing schema definition by supplying it as a second parameter to the Schema constructor:

var appFormSchema = new Schema({
    User_id : {type: String},
    LogTime : {type: String},
    feeds : [new Schema({
        Name: {type: String},
        Text : {type: String}
    }, {strict: false})
    ]
}, {strict: false});

module.exports = mongoose.model('appForm', appFormSchema);

If you want to leave feeds as fully schemaless, that's where you can used Mixed:

var appFormSchema = new Schema({
    User_id : {type: String},
    LogTime : {type: String},
    feeds : [Schema.Types.Mixed]
}, {strict: false});

module.exports = mongoose.model('appForm', appFormSchema);

Diapositive

That code works and posts default form data:user_id,LogTime and feeds array and its object but as I add another property into feeds array like:customText, it doesn't update that customText but the rest...I ll search where I am still doing something wrong..thanks anyway! – Carlie

If you want to add arbitrary properties to feeds, then the option needs to be set on that embedded schema as well. See the updated answer. – Diapositive

YES!!!:) second option is exactly what I am trying to do for hours! Thanks a lot! – Carlie

@Diapositive can you please help and tell how to write a schema for inserting the json data into such appFormSchema ? I mean i am sending such complex json from my app to server, where rest api uses my predefined model schema to insert the data .Thing is while inserting i have diff number of json object in the feeds array so how to map them in db? – Vapid

Answer 2

In the latest version of Mongoose, you can use something like this

const mongoose = require("mongoose");
const { Schema } = mongoose;

const assetSchema = new Schema(
  { name: { type: String, required: true } },
  { timestamps: { createdAt: "created_at", updatedAt: "updated_at" } }
);

const Asset = mongoose.model("Asset", assetSchema);

const addDynamicField = (fieldName, type) => {
  assetSchema.add({ [fieldName]: { type, default: null } });
};

module.exports = { Asset, addDynamicField };

we can set propertyName and it's type

Eg:

propertyName = "age"
propertyType = "Number"

addDynamicField(propertyName, propertyType);

This will create a dynamic property in the schema and also there is no need of using {strict: false}.

Funk