var ExampleObject = function( array ) {

   this.array = array; 

};

​

// the methods we want to implement

// in our object

var utilityMethods = [ 'indexOf', 'filter' ],

    slice          = [].slice;

​

// iterate over the wished methods

_.each( utilityMethods, function( method ) {

  ExampleObject.prototype[ method ] = function() {

    var args = slice.call( arguments );

    args.unshift( this.array );

    return _[ method ].apply( _, args );

  };

});

​

// create the new object

var example = new ExampleObject( [ 5, 4, 3, 2, 1 ] );

​

// proof that indexOf works

console.log( example.indexOf( 2 ) );

​

// proof that filter workds

console.log(

  example.filter( function( value ) {

    return value % 2;

  } )

);

​