Hello:

I have a schema, but when my user is using a form, I want to validate onkeypress only the particular field they've modified, using the overarching schema that the form already composes.

// purely hypothetical, but 
var schema = { a: joi.string(), b: joi.string() };
onkeypress = function(evt) {
    joi.validate(evt.target.value, schema.a); // where i could extract a's schema rules only
}

is such a feature available?