Заимствование методов в JavaScript

borrow.js

var slice = Function
  .prototype
  .call
  .bind(Array.prototype.slice);
  
var args = slice(arguments);

  
// Пример
// http://davidshariff.com/blog/borrowing-methods-in-javascript/
var scoreCalculator = {
    getSum: function(results) {
        var score = 0;
        for (var i = 0, len = results.length; i < len; i++) {
            score = score + results[i];
        }
        return score;
    },
    getScore: function() {
        return scoreCalculator.getSum(this.results) / this.handicap;
    }
};

var player1 = {
    results: [69, 50, 76],
    handicap: 8
};

var player2 = {
    results: [23, 4, 58],
    handicap: 5
};

var score = Function.prototype.call.bind(scoreCalculator.getScore);

// Score: 24.375
console.log('Score: ' + score(player1));

// Score: 17
console.log('Score: ' + score(player2));