JavaScript - Introducing Functions: Getting functional(scopes, global, local)

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 3(Introducing Functions: Getting functional)、EXERCISE(p.110)を解いてみる。

EXERCISE(p.110)

コード(BBEdit, Emacs)

var result = '',
    n,
    clunkCounter = 0,
    clunk = function (times) {
        var num = times;
        
        while (num > 0) {
            display("clunk");
            num = num - 1;
        }
    },
    thingamajig = function (size) {
        var facky = 1;
        
        if (size === 0) {
            display("clank");
        } else if (size === 1) {
            display("thunk");
        } else {
            while (size > 1) {
                facky = facky * size;
                size = size - 1;
            }
            clunk(facky);
        }
    },
    display = function (output) {
        result += output + '\n';
        clunkCounter += 1;
    };

n = prompt('m = ');
n = parseInt(n, 10);

// 0 clank 1
// 1 thunk 2
// 2 clunk clunk 2
// 3 clunk clunk clunk clunk clunk clunk 6
// 4 clunk … clunk 24
// 5 clunk … clunk 120
thingamajig(n);
result += clunkCounter + '\n';

print(result);