Function is not called when defined-CodePudding

I am pretty sure I am defining the instance method as a function but am getting the error TypeError: foundProduct.toggleOnSale is not a function when calling the line marked with <-- . I don't understand why this is happening.

const Product = mongoose.model('Product', productSchema)

productSchema.methods.toggleOnSale = function() {
    this.onSale = !this.onSale;
    return this.save();
}

const findProduct = async () => {
    const foundProduct = await Product.findOne({ name: 'Mountain Bike' });
    console.log(foundProduct)
    await foundProduct.toggleOnSale() <--
    console.log(foundProduct)
}

CodePudding user response：

I think you might want to try defining the methods on the schema before deriving the model class out of it:

const productSchema = /* ... */;

productSchema.methods.toggleOnSale = function() {
    this.onSale = !this.onSale;
    return this.save();
}

const Product = mongoose.model('Product', productSchema)