JavaScript - Creating objects - Advanced Object Construction(methods)

Head First JavaScript Programming

開発環境

• macOS Sierra - Apple (OS)
• Emacs (Text Editor)
• JavaScript (プログラミング言語)
• Safari(Web browser)

Head First JavaScript Programming (Eric T. Freeman (著)、Elisabeth Robson (著)、O'Reilly Media)の Chapter 12.(Creating objects - Advanced Object Construction)の EXERCISE(No. 7719)を取り組んでみる。

EXERCISE(No. 7719)

コード(Emacs)

HTML5

<pre id="output0"></pre>
<button id="run0">run</button>
<button id="clear0">clear</button>
<script src="sample2.js"></script>

JavaScript

let btn0 = document.querySelector('#run0'),
    btn1 = document.querySelector('#clear0'),
    pre0 = document.querySelector('#output0'),
    p = (x) => pre0.textContent += x + '\n',
    range = (start, end, step=1) => {
        let result = [];
        for (let i = start; i < end; i += 1) {
            result.push(i);
        }
        return result;
    };

let Coffee = (roast, ounces) => {
    let that = {},
        getSize = () =>
        ounces === 8 ? 'small' :
        12 === ounces ? 'medium' : 'larg',
        toString = () => `You've ordered a ${getSize()} ${roast} coffee.`;
    
    that.toString = toString;

    return that;
};

let output = () => {
    let houseBlend = Coffee('House Blend', 12);

    p(houseBlend.toString());

    let darkRoast = Coffee('Dark Roast', 16);
    p(darkRoast.toString());
};

let clear = () => pre0.textContent = '';

btn0.onclick = output;
btn1.onclick = clear;

output();