2017年4月18日火曜日

開発環境

メタプログラミングRuby 第2版(Paolo Perrotta (著)、角 征典 (翻訳)、オライリージャパン)の1部(メタプログラミング Ruby)、2章(月曜日: オブジェクトモデル)、2.4(メソッドを呼び出すときに何が起きているの?)、2.4.3(Refinements)、Refinements を捕まえた、を JavaScript で取り組んでみる。

HTML5

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

<script src="sample8.js"></script>

JavaScript

let btn0 = document.querySelector('#run0'),
    btn1 = document.querySelector('#clear0'),
    pre0 = document.querySelector('#output0'),
    p = (x) => pre0.textContent += x + '\n';

let StringExtentions = (spec) => {
    let that = {},
        defaultToAlphanumeric = String.prototype.toAlphanumeric,
        defaultReverse = String.prototype.reverse,
        defaults = [['toAlphanumeric', defaultToAlphanumeric],
                    ['reverse', defaultReverse]],
        on = () => {
            String.prototype.toAlphanumeric = function () {
                return this.replace(/[^\w\s]/g, '');
            };
            String.prototype.reverse = () => {
                return 'esrever';
            };
        },
        off = () => {
            defaults.forEach((x) => {
                String.prototype[x[0]] = x[1];
            });
        };

    that.on = on;
    that.off = off;

    return that;
};

let StringStuff = (spec) => {
    let that = {},
        se = StringExtentions();

    se.on();
    p('myString'.reverse());
    se.off();

    return that;
};

let MyClass = (spec) => {
    let that = {},
        myMethod = () => 'original myMethod',
        anotherMethod = () => myMethod();

    that.myMethod = myMethod;
    that.anotherMethod = anotherMethod;

    return that;
};

let output = () => {
    let se = StringExtentions();
    try {
        p('my *1st* refinement!'.toAlphanumeric());
    } catch (e) {
        p(e);
    }
    se.on();
    try {
        p('my *1st* refinement!'.toAlphanumeric());
    } catch (e) {
        p(e);
    }
    se.off();
    try {
        p('my *1st* refinement!'.toAlphanumeric());
    } catch (e) {
        p(e);
    }
    StringStuff();
    p('Refinements を捕まえた');
    let obj = MyClass();
    let t = obj.myMethod;
    obj.myMethod = () => 'refined myMethod';
    p(obj.myMethod());
    p(obj.anotherMethod());
    obj.myMethod = t;
    p(obj.myMethod());
    p(obj.anotherMethod());
};

btn0.onclick = output;
btn1.onclick = () => {
    pre0.textContent = '';
};

output();


  






 
						

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