Custom Knockout validation and Knockout Mapping

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I'm using knockout mapping to bind a model from the server and then i'm adding validation to it. So far so good.

I have a list of products that have constraints on the collection and the individual product data. Since I don't generate the class in javascript for the observableArray, i'm having difficulty understanding how I can extend it so I can add validation to the product class within the observable array.

I get the feeling that this may not be possible if I don't create and extend the object in javascript.

 $.getJSON("api/Companies/Products", function (model) {
            var serverModel = ko.mapping.fromJS(model);

            // Normal object - Fine
            serverModel.someObject.Extend({ required: { params: true, message: 'Required' });
            // products is an observable array of 'product'
            serverModel.products.Extend({
                validation: [ {
                    validator: function (val, count) {
                        return val.length > count;
                    },
                    message: 'At least one product must be entered',
                    params: 0
                }]
            });
            // How do I extend product??
            serverModel.products.product.extend({ ...? });

I don't really want to loop through and check them individually as I want the error message next to the item and for performance reasons.

asked 1 min ago

Peter Lea

32