MongoDB: output 'id' instead of '_id'


Question

I am using mongoose (node), what is the best way to output id instead of _id?

1
49
8/12/2011 1:46:37 AM

Accepted Answer

I create a toClient() method on my models where I do this. It's also a good place to rename/remove other attributes you don't want to send to the client:

Schema.method('toClient', function() {
    var obj = this.toObject();

    //Rename fields
    obj.id = obj._id;
    delete obj._id;

    return obj;
});
30
8/12/2011 10:05:48 AM

Given you're using Mongoose, you can use 'virtuals', which are essentially fake fields that Mongoose creates. They're not stored in the DB, they just get populated at run time:

// Duplicate the ID field.
Schema.virtual('id').get(function(){
    return this._id.toHexString();
});

// Ensure virtual fields are serialised.
Schema.set('toJSON', {
    virtuals: true
});

Any time toJSON is called on the Model you create from this Schema, it will include an 'id' field that matches the _id field Mongo generates. Likewise you can set the behaviour for toObject in the same way.

See:

You can abstract this into a BaseSchema all your models then extend/invoke to keep the logic in one place. I wrote the above while creating an Ember/Node/Mongoose app, since Ember really prefers to have an 'id' field to work with.


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