266 mass apply rules

[stevegreatrex]

The is a suggested implementation of setRules that will let you set validations on an entire object graph from a single definition.

var rules = {
    //will apply required, min & max to viewModel.property
    property: {
        required: true,
        min: 10,
        max: 99,
    },

    //will apply required to viewModel.property2.childProperty
    property2: {
        childProperty: { required: true }
    },

    //will apply email to the elementProperty of each item in
    //viewModel.arrayProperty
    arrayProperty: {
        elementProperty: { email: true }
    }
};

var viewModel = {
    property: ko.observable(),
    property2: {
        childProperty: ko.observable()
    },
    arrayProperty: ko.observableArray([
        { elementProperty: ko.observable() },
        { elementProperty: ko.observable() }
    ])
};

ko.validation.setRules(target, rules);    

Eventually this could be used to pull validation definitions from models, from ASP.NET DataAnnotations, or from any other source.

Any comments/changes/improvements?

[stevegreatrex]

Fixes #266

[pitus]

If any rules are applied to an observableArray property, there should be an option to re-apply them if the array changes, otherwise only the initial array's set of values will be validated. Perhaps subscribe to the observableArray property and re-apply the rule set to added values ?