JavaScript - Understanding Objects: A trip to Objectville(How this works)

Head First JavaScript Programming
( O'Reilly Media)
Eric T. Freeman (著), Elisabeth Robson (著)

開発環境

• OS X Mavericks - Apple(OS)
• Safari, Firefox + Firebug, Google Chrome(Webプラウザ、プラグイン)
• BBEdit - Bare Bones Software, Inc. (GUI) , Emacs (CUI) (Text Editor)
• JavaScript (プログラミング言語)

Head First JavaScript Programming (Eric T. Freeman (著)、 Elisabeth Robson (著)、 O'Reilly Media )のChapter 5(Understanding Objects: A trip to Objectville)、SHARPEN YOUR PENCIL(p.205)を解いてみる。

SHARPEN YOUR PENCIL(p.205)

コード(BBEdit, Emacs)

var eightBall = {
        index: 0,
        advice: ['yes', 'no', 'maybe', 'not a chance'],
        shake: function () {
            this.index += 1;
            if (this.index >= this.advice.length) {
                this.index = 0;
            }
        },
        look: function () {
            return this.advice[this.index];
        }
    };

eightBall.shake();
print(eightBall.look());
eightBall.shake();
print(eightBall.look());
eightBall.shake();
print(eightBall.look());
eightBall.shake();
print(eightBall.look());
eightBall.shake();
print(eightBall.look());