Today I released a new version of my JavaScript Design-by-Contract Library (dbc). As well as documentation and other minor improvements the two big new features are:

makeConstructor

MakeConstructor generates a constructor from a spec. The constructor validates that the created objects meet the spec. ie

    var Person = dbc.MakeConstructor({
       name: [{validator:'type',args:'string'}],
       age: [{validator:'type',args:'number'}]
    });
    Person.prototype.canDrive = dbc.wrap(function () { 
         return this.age > 16;
    }, null, [{validator:'type',args:'number'}]);
    var p = new Person('John', 22);
    p.canDrive(); // true 

wrap

Wrap returns a wrapped function that applies ‘specs’ validators to the functions arguments and ‘returnSpec’ validators to the return value. eg

var add = dbc.wrap(function (f,s) { 
    return f + s;
}, {
    // validators for the first arg
    0: [{validator:'type', args:['number']}],
    // validators for the second arg
    1:[{validator:'type', args:['number']}]
},
    // validators for the return value 
    [{validator: 'type', args:['number']}]);

Dbc is available on github or via npm

npm install dbc