` markup. 🎉
-
-### Ternary vs Logical AND
-
-As you can see, ternaries are wonderful for `if/else` conditions. But what about simple `if` conditions?
-
-Let’s look at another example. If `isPro` (a boolean) is `true`, we are to display a trophy emoji. We are also to render the number of stars (if not zero). We could go about it like this.
-
-```
-const MyComponent = ({ name, isPro, stars}) => (
-
-
- Hello {name}
- {isPro ? '🏆' : null}
-
- {stars ? (
-
- Stars:{'⭐️'.repeat(stars)}
-
- ) : null}
-
-);
-```
-
-But notice the “else” conditions return `null`. This is becasue a ternary expects an else condition.
-
-For simple `if` conditions, we could use something a little more fitting: the logical AND operator. Here’s the same code written using a logical AND.
-
-```
-const MyComponent = ({ name, isPro, stars}) => (
-
-
- Hello {name}
- {isPro && '🏆'}
-
- {stars && (
-
- Stars:{'⭐️'.repeat(stars)}
-
- )}
-
-);
-```
-
-Not too different, but notice how we eliminated the `: null` (i.e. else condition) at the end of each ternary. Everything should render just like it did before.
-
-
-Hey! What gives with John? There is a `0` when nothing should be rendered. That’s the gotcha that I was referring to above. Here’s why.
-
-[According to MDN][3], a Logical AND (i.e. `&&`):
-
-> `expr1 && expr2`
-
-> Returns `expr1` if it can be converted to `false`; otherwise, returns `expr2`. Thus, when used with Boolean values, `&&` returns `true` if both operands are true; otherwise, returns `false`.
-
-OK, before you start pulling your hair out, let me break it down for you.
-
-In our case, `expr1` is the variable `stars`, which has a value of `0`. Because zero is falsey, `0` is returned and rendered. See, that wasn’t too bad.
-
-I would write this simply.
-
-> If `expr1` is falsey, returns `expr1`, else returns `expr2`.
-
-So, when using a logical AND with non-boolean values, we must make the falsey value return something that React won’t render. Say, like a value of `false`.
-
-There are a few ways that we can accomplish this. Let’s try this instead.
-
-```
-{!!stars && (
-
- {'⭐️'.repeat(stars)}
-
-)}
-```
-
-Notice the double bang operator (i.e. `!!`) in front of `stars`. (Well, actually there is no “double bang operator”. We’re just using the bang operator twice.)
-
-The first bang operator will coerce the value of `stars` into a boolean and then perform a NOT operation. If `stars` is `0`, then `!stars` will produce `true`.
-
-Then we perform a second NOT operation, so if `stars` is 0, `!!stars` would produce `false`. Exactly what we want.
-
-If you’re not a fan of `!!`, you can also force a boolean like this (which I find a little wordy).
-
-```
-{Boolean(stars) && (
-```
-
-Or simply give a comparator that results in a boolean value (which some might say is even more semantic).
-
-```
-{stars > 0 && (
-```
-
-#### A word on strings
-
-Empty string values suffer the same issue as numbers. But because a rendered empty string is invisible, it’s not a problem that you will likely have to deal with, or will even notice. However, if you are a perfectionist and don’t want an empty string on your DOM, you should take similar precautions as we did for numbers above.
-
-### Another solution
-
-A possible solution, and one that scales to other variables in the future, would be to create a separate `shouldRenderStars` variable. Then you are dealing with boolean values in your logical AND.
-
-```
-const shouldRenderStars = stars > 0;
-```
-
-```
-return (
-
- {shouldRenderStars && (
-
- {'⭐️'.repeat(stars)}
-
- )}
-
-);
-```
-
-Then, if in the future, the business rule is that you also need to be logged in, own a dog, and drink light beer, you could change how `shouldRenderStars` is computed, and what is returned would remain unchanged. You could also place this logic elsewhere where it’s testable and keep the rendering explicit.
-
-```
-const shouldRenderStars =
- stars > 0 && loggedIn && pet === 'dog' && beerPref === 'light`;
-```
-
-```
-return (
-
- {shouldRenderStars && (
-
- {'⭐️'.repeat(stars)}
-
- )}
-
-);
-```
-
-### Conclusion
-
-I’m of the opinion that you should make best use of the language. And for JavaScript, this means using conditional ternary operators for `if/else`conditions and logical AND operators for simple `if` conditions.
-
-While we could just retreat back to our safe comfy place where we use the ternary operator everywhere, you now possess the knowledge and power to go forth AND prosper.
-
---------------------------------------------------------------------------------
-
-作者简介：
-
-Managing Editor at the American Express Engineering Blog http://aexp.io and Director of Engineering @AmericanExpress. MyViews !== ThoseOfMyEmployer.
-
-----------------
-
-via: https://medium.freecodecamp.org/conditional-rendering-in-react-using-ternaries-and-logical-and-7807f53b6935
-
-作者：[Donavon West][a]
-译者：[译者ID](https://github.com/译者ID)
-校对：[校对者ID](https://github.com/校对者ID)
-
-本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
-
-[a]:https://medium.freecodecamp.org/@donavon
-[1]:https://unsplash.com/photos/pKeF6Tt3c08?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText
-[2]:https://unsplash.com/search/photos/road-sign?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText
-[3]:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_Operators
diff --git a/translated/tech/20180201 Conditional Rendering in React using Ternaries and.md b/translated/tech/20180201 Conditional Rendering in React using Ternaries and.md
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@@ -0,0 +1,205 @@
+在 React 条件渲染中使用三元表达式和 “&&”
+============================================================
+
+
+Photo by [Brendan Church][1] on [Unsplash][2]
+
+React 组件可以通过多种方式决定渲染内容。你可以使用传统的 if 语句或 switch 语句。在本文中，我们将探讨一些替代方案。但要注意，如果你不小心，有些方案会带来自己的陷阱。
+
+### 三元表达式 vs if/else
+
+假设我们有一个组件被传进来一个 `name` prop。 如果这个字符串非空，我们会显示一个问候语。否则，我们会告诉用户他们需要登录。
+
+这是一个只实现了如上功能的无状态函数式组件。
+
+```
+const MyComponent = ({ name }) => {
+ if (name) {
+ return (
+
+ Hello {name}
+
+ );
+ }
+ return (
+
+ Please sign in
+
+ );
+};
+```
+
+这个很简单但是我们可以做得更好。这是使用三元运算符编写的相同组件。
+
+```
+const MyComponent = ({ name }) => (
+
+ {name ? `Hello ${name}` : 'Please sign in'}
+
+);
+```
+
+请注意这段代码与上面的例子相比是多么简洁。
+
+有几点需要注意。因为我们使用了箭头函数的单语句形式，所以隐含了return语句。另外，使用三元运算符允许我们省略掉重复的 `
` 标记。🎉
+
+### 三元表达式 vs &&
+
+正如您所看到的，三元表达式用于表达 if/else 条件式非常好。但是对于简单的 if 条件式怎么样呢？
+
+让我们看另一个例子。如果 isPro（一个布尔值）为真，我们将显示一个奖杯表情符号。我们也要渲染星星的数量（如果不是0）。我们可以这样写。
+
+```
+const MyComponent = ({ name, isPro, stars}) => (
+
+
+ Hello {name}
+ {isPro ? '🏆' : null}
+
+ {stars ? (
+
+ Stars:{'⭐️'.repeat(stars)}
+
+ ) : null}
+
+);
+```
+
+请注意 “else” 条件返回 null 。 这是因为三元表达式要有"否则"条件。
+
+对于简单的 “if” 条件式，我们可以使用更合适的东西：&& 运算符。这是使用 “&&” 编写的相同代码。
+
+```
+const MyComponent = ({ name, isPro, stars}) => (
+
+
+ Hello {name}
+ {isPro && '🏆'}
+
+ {stars && (
+
+ Stars:{'⭐️'.repeat(stars)}
+
+ )}
+
+);
+```
+
+没有太多区别，但是注意我们消除了每个三元表达式最后面的 `: null` （else 条件式）。一切都应该像以前一样渲染。
+
+
+嘿！约翰得到了什么？当什么都不应该渲染时，只有一个0。这就是我上面提到的陷阱。这里有解释为什么。
+
+[根据 MDN][3]，一个逻辑运算符“和”（也就是`&&`）：
+
+> `expr1 && expr2`
+
+> 如果 `expr1` 可以被转换成 `false` ，返回 `expr1`；否则返回 `expr2`。 如此，当与布尔值一起使用时，如果两个操作数都是 true，`&&` 返回 `true` ；否则，返回 `false`。
+
+好的，在你开始拔头发之前，让我为你解释它。
+
+在我们这个例子里， `expr1` 是变量 `stars`，它的值是 `0`，因为0是 falsey 的值, `0` 会被返回和渲染。看，这还不算太坏。
+
+我会简单地这么写。
+
+> 如果 `expr1` 是 falsey，返回 `expr1` ，否则返回 `expr2`
+
+所以，当对非布尔值使用 “&&” 时，我们必须让 falsy 的值返回 React 无法渲染的东西，比如说，`false` 这个值。
+
+我们可以通过几种方式实现这一目标。让我们试试吧。
+
+```
+{!!stars && (
+
+ {'⭐️'.repeat(stars)}
+
+)}
+```
+
+注意 `stars` 前的双感叹操作符（ `!!`）（呃，其实没有双感叹操作符。我们只是用了感叹操作符两次）。
+
+第一个感叹操作符会强迫 `stars` 的值变成布尔值并且进行一次“非”操作。如果 `stars` 是 `0` ，那么 `!stars` 会 是 `true`。
+
+然后我们执行第二个`非`操作，所以如果 `stars` 是0，`!!stars` 会是 `false`。正好是我们想要的。
+
+如果你不喜欢 `!!`，那么你也可以强制转换出一个布尔数比如这样（这种方式我觉得有点冗长）。
+
+```
+{Boolean(stars) && (
+```
+
+或者只是用比较符产生一个布尔值（有些人会说这样甚至更加语义化）。
+
+```
+{stars > 0 && (
+```
+
+#### 关于字符串
+
+空字符串与数字有一样的毛病。但是因为渲染后的空字符串是不可见的，所以这不是那种你很可能会去处理的难题，甚至可能不会注意到它。然而，如果你是完美主义者并且不希望DOM上有空字符串，你应采取我们上面对数字采取的预防措施。
+
+### 其它解决方案
+
+一种可能的将来可扩展到其他变量的解决方案，是创建一个单独的 `shouldRenderStars` 变量。然后你用“&&”处理布尔值。
+
+```
+const shouldRenderStars = stars > 0;
+```
+
+```
+return (
+
+ {shouldRenderStars && (
+
+ {'⭐️'.repeat(stars)}
+
+ )}
+
+);
+```
+
+之后，在将来，如果业务规则要求你还需要已登录，拥有一条狗以及喝淡啤酒，你可以改变 `shouldRenderStars` 的得出方式，而返回的内容保持不变。你还可以把这个逻辑放在其它可测试的地方，并且保持渲染明晰。
+
+```
+const shouldRenderStars =
+ stars > 0 && loggedIn && pet === 'dog' && beerPref === 'light`;
+```
+
+```
+return (
+
+ {shouldRenderStars && (
+
+ {'⭐️'.repeat(stars)}
+
+ )}
+
+);
+```
+
+### 结论
+
+我认为你应该充分利用这种语言。对于 JavaScript，这意味着为 `if/else` 条件式使用三元表达式，以及为 `if` 条件式使用 `&&` 操作符。
+
+我们可以回到每处都使用三元运算符的舒适区，但你现在消化了这些知识和力量，可以继续前进 && 取得成功了。
+
+--------------------------------------------------------------------------------
+
+作者简介：
+
+美国运通工程博客的执行编辑 http://aexp.io 以及 @AmericanExpress 的工程总监。MyViews !== ThoseOfMyEmployer.
+
+----------------
+
+via: https://medium.freecodecamp.org/conditional-rendering-in-react-using-ternaries-and-logical-and-7807f53b6935
+
+作者：[Donavon West][a]
+译者：[GraveAccent](https://github.com/GraveAccent)
+校对：[校对者ID](https://github.com/校对者ID)
+
+本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
+
+[a]:https://medium.freecodecamp.org/@donavon
+[1]:https://unsplash.com/photos/pKeF6Tt3c08?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText
+[2]:https://unsplash.com/search/photos/road-sign?utm_source=unsplash&utm_medium=referral&utm_content=creditCopyText
+[3]:https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_Operators