JavaScript - Arrays - Putting Some Order in Your Data(index, size)

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 4.(Arrays - Putting Some Order in Your Data)、How the while loop works の SHARPEN YOUR PENCIL(No. No 2349) を取り組んでみる。

SHARPEN YOUR PENCIL(No. No 2349)

コード(Emacs)

HTML5

<button id="run0">run</button><button id="clear0">clear</button>
<pre id="output0"></pre>

<script src="sample1.js"></script>

JavaScript

let btn0 = document.querySelector('#run0'),
    btn1 = document.querySelector('#clear0'),
    pre0 = document.querySelector('#output0');

let products = ['Choo Choo Chocolate',
                'Icy Mint',
                'Cake Batter',
                'Bubblegum'],
    last = products.length - 1,
    recent = products[last];
    
btn0.onclick = () => {
    pre0.textContent = recent;
};

btn1.onclick = () => {
    pre0.textContent = '';
};