excludeFromIndexes()

When you create a Schemaless Models (with explicityOnly set to false on your Schema), all the properties not declared explicitly will automatically be added to your indexes in the Datastore.

If you don't want this behaviour you can call Model.excludeFromIndexes(property) passing a string property or an Array of properties. If one of the property passed is already declared on the Schema, this method will set its excludeFromIndexes value to true.

Example:

// Your model declaration

const options = { explicitOnly: false };
const blogPostSchema = new Schema({
    title: { type: String }
}, options);

BlogPost = gstore.model('BlogPost', blogPostSchema);

...

// Yout controller

const blogPost = new BlogPost({
    title:'my-title',
    text:`some very long text that can not be indexed because of the limitation
            of the Datastore where the max length is 1,500 bytes for text properties.
            It takes 1 to 6 bytes for 1 UTF-8 char ~= 500 characters`
    });

/*
If you save this entity, the text won't be saved in the Datastore
because of the size limitation of the indexes (can't be more that 1500 bytes).

https://cloud.google.com/datastore/docs/concepts/limits

Assuming that the "text" propery is dynamic and is not known at Schema instantiation,
you need to remove the propery from indexes before saving.
*/

BlogPost.excludeFromIndexes('text');

// now you can save the entity
blogPost.save().then(() => { ... });