blocks|key|1850353|text|这里是一种无分点的方法。您要查找的主要函数是pipe、evolve和converge。我不确定这是不是最好的方法，这是我能想到的最好的方法：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1850354|​|1850355|const+{+add,+converge,+evolve,+map,+multiply,+pipe,+prop,+subtract+}+=+R;

const+myNumbers+=+[
++++{+top:+10,+bottom:+5,+rate:+5+},
++++{+top:+9,+bottom:+4,+rate:+3+},
];

const+process+=+pipe(

++++evolve({
++++++++top:+add(10),
++++++++bottom:+multiply(2),
++++}),

++++converge(multiply,+[

++++++++converge(subtract,+[
++++++++++++prop('bottom'),
++++++++++++prop('top'),
++++++++]),

++++++++prop('rate'),
++++]),
);

console.log(map(process,+myNumbers));|code-block|syntax|javascript|1850356|<script+src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>|1850357|1850358|entityMap^0|M|4|R|6|Y|8|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]|$9|U|A|V|B|C]|$9|W|A|X|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Y|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|Z|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|J|7|10|8|@]|D|@]|E|$K|L]]|$1|O|3|G|5|6|7|11|8|@]|D|@]|E|$]]|$1|P|3|-4|5|6|7|12|8|@]|D|@]|E|$]]]|Q|$]]

<p>Here is <em>a</em> point-free approach. The main functions you're looking for are <code>pipe</code>, <code>evolve</code> and <code>converge</code>. I'm not sure if this is the <em>best</em> way, it's just the best I could think of:</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>const { add, converge, evolve, map, multiply, pipe, prop, subtract } = R;

const myNumbers = [
    { top: 10, bottom: 5, rate: 5 },
    { top: 9, bottom: 4, rate: 3 },
];

const process = pipe(

    evolve({
        top: add(10),
        bottom: multiply(2),
    }),

    converge(multiply, [

        converge(subtract, [
            prop('bottom'),
            prop('top'),
        ]),

        prop('rate'),
    ]),
);

console.log(map(process, myNumbers));</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"&gt;&lt;/script&gt;</code></pre>
</div>
</div>
</p>


blocks|key|1850435|text|如果这是一个编写无指针代码的练习，像@JeffreyWesterkamp这样的解决方案是很好的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1850436|然而，对于生产代码，任何无指针的解决方案都将比这个简单版本的可读性差得多：|1850437|​|1850438|const+process+=+({top,+bottom,+rate})+=>+((2+*+bottom)+-+(10+%2B+top))+*+rate;

const+myNumbers+=+[
++++{+top:+10,+bottom:+5,+rate:+5+},
++++{+top:+9,+bottom:+4,+rate:+3+},
];

console.log(R.map(process,+myNumbers));|code-block|syntax|javascript|1850439|<script+src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.js"></script>|1850440|1850441|重点是不要迷恋无关紧要的东西。它是一个工具，有时使代码更容易阅读，更容易理解。但如果它不这样做，它就不值得使用。|1850442|别误会我的意思。我是无指针代码的铁杆粉丝，Ramda+(免责声明:我是它的作者之一)有一些有用的工具来帮助你编写它。但是Ramda在其他代码中工作得很好。所以要明智地使用它。|1850443|1850444|还有一点(嗯)：Ramda提供了两个非常不寻常的函数，useWith和converge，使编写无指针代码变得更容易。但是converge通常可以被更标准的lift所取代。它不能总是被替换，因为它有一些lift不提供的处理可变函数的特性，但是当您可以使用lift时，我建议您这样做。例如，它不是|offset|length|style|CODE|1850445|converge(subtract,+[prop('bottom'),+prop('top')])|1850446|你可以这样写|1850447|lift(subtract)(prop('bottom'),+prop('top'))|1850448|据我所知，目前还没有useWith的标准替代品。但只要有可能，我都会用lift替换converge。|1850449|entityMap^0|0|0|0|0|0|0|0|0|0|R|7|Z|8|1O|8|25|4|2S|4|3I|4|0|0|0|0|A|7|Z|4|15|8|0^^$0|@$1|2|3|4|5|6|7|18|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|19|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|1A|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|1B|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|H|7|1C|8|@]|9|@]|A|$I|J]]|$1|M|3|E|5|6|7|1D|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|1E|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|1F|8|@]|9|@]|A|$]]|$1|R|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1H|8|@$U|1I|V|1J|W|X]|$U|1K|V|1L|W|X]|$U|1M|V|1N|W|X]|$U|1O|V|1P|W|X]|$U|1Q|V|1R|W|X]|$U|1S|V|1T|W|X]]|9|@]|A|$]]|$1|Y|3|Z|5|H|7|1U|8|@]|9|@]|A|$I|J]]|$1|10|3|11|5|6|7|1V|8|@]|9|@]|A|$]]|$1|12|3|13|5|H|7|1W|8|@]|9|@]|A|$I|J]]|$1|14|3|15|5|6|7|1X|8|@$U|1Y|V|1Z|W|X]|$U|20|V|21|W|X]|$U|22|V|23|W|X]]|9|@]|A|$]]|$1|16|3|-4|5|6|7|24|8|@]|9|@]|A|$]]]|17|$]]

<p>If this is an exercise in writing point-free code, a solution like the one from @JeffreyWesterkamp is fine.</p>

<p>For production code, though, any point-free solution is going to be a <em>lot</em> less readable than this simple version:</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>const process = ({top, bottom, rate}) =&gt; ((2 * bottom) - (10 + top)) * rate;

const myNumbers = [
    { top: 10, bottom: 5, rate: 5 },
    { top: 9, bottom: 4, rate: 3 },
];

console.log(R.map(process, myNumbers));</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="//cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.js"&gt;&lt;/script&gt;</code></pre>
</div>
</div>
</p>

<p>The point is to not make a fetish over point-free.  It is a tool that sometimes makes code easier to read, easier to understand.  But it's not worth using if it doesn't do so.</p>

<p>Don't get me wrong.  I'm a big fan of point-free code, and Ramda (disclaimer: I'm one of its authors) has some useful tools to help you write it.  But Ramda works just fine with other code.  So use it wisely.</p>

<hr>

<p>One other point (ahem): Ramda supplies two fairly unusual functions, <code>useWith</code> and <code>converge</code>, to make it easier to write point-free code.  But <code>converge</code> can often be replaced by the more standard <code>lift</code>. It can't always be replaced, as it has some features for handling variadic functions that <code>lift</code> does not supply, but when you can use <code>lift</code>, I would suggest that you do so.  For instance, instead of</p>

<pre><code>converge(subtract, [prop('bottom'), prop('top')])
</code></pre>

<p>you might write</p>

<pre><code>lift(subtract)(prop('bottom'), prop('top'))
</code></pre>

<p>There's no standard replacement for <code>useWith</code> that I know of.  But I would replace <code>converge</code> with <code>lift</code> whenever possible.</p>


<p>I have an array of objects</p>

<pre><code>const myNumbers = [
  {
   top: 10,
   bottom: 5,
   rate: 5
  },
  {
   top: 9,
   bottom: 4,
   rate: 3
  },
];
</code></pre>

<p>I want to run a few functions that make the numbers usable before I do anything with them;</p>

<pre><code>const addTen = r.add(10);
const double = r.multiply(2);
</code></pre>

<p>And a function that accepts the numbers and does some maths:</p>

<pre><code>const process = (top, bottom, rate) =&gt; r.multiply(r.subtract(bottom, top), rate)
</code></pre>

<p>So my final function looks like</p>

<pre><code>muNymbers.map(({ top, bottom, rate }) =&gt;
  process(addTen(top), double(bottom), rate)
);
</code></pre>

<p>Just looking at this code you can see both functions are already becoming very nested and not particularly clear. My real problem is slightly more complicated again, and I am struggling to see how I can make this point-free when picking different values for different operations.</p>


How to write point-free functional JS using Ramda

我有一个对象数组const myNumbers = [  {   top: 10,   bottom: 5,   rate: 5  },  {   top: 9,   bottom: 4,   rate: 3  },];在我对数字做任何事情之前，我想运行一些函数使它们变得可用；const addTen = r.add(...

问如何使用Ramda编写无指针的函数式JS
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