ES6 translate new #51
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S1ngS1ng
suggested changes
Aug 1, 2018
| @@ -292,37 +292,37 @@ | |||
| "id": "587d7b87367417b2b2512b43", | |||
| "title": "Use Arrow Functions to Write Concise Anonymous Functions", | |||
| "description": [ | |||
| "In JavaScript, we often don't need to name our functions, especially when passing a function as an argument to another function. Instead, we create inline functions. We don't need to name these functions because we do not reuse them anywhere else.", | |||
| "To achieve this, we often use the following syntax:", | |||
| "在JavaScript里，我们会经常遇到不需要给函数命名的情况，尤其是在需要将以个函数作为参数传给另外一个函数的时候，在这些时候，我们会创建行内函数。因为这些函数不会再其他地方复用，所以我们不要给它们命名。", | |||
| "Arrow functions work really well with higher order functions, such as <code>map()</code>, <code>filter()</code>, and <code>reduce()</code>, that take other functions as arguments for processing collections of data.", | ||
| "Read the following code:", | ||
| "我们已经见识到了箭头函数在处理数据时候的强大之处。", | ||
| "箭头函数在类似 <code>map</code>, <code>filter</code>, <code>reduce</code> 等需要其他函数作为参数来处理数据的高阶函数里会很好用。" , |
| "<blockquote>FBPosts.filter((post) => post.thumbnail !== null && post.shares > 100 && post.likes > 500)</blockquote>", | ||
| "This code is more succinct and accomplishes the same task with fewer lines of code.", | ||
| "这段代码完成了同样的任务，却变得更加剪短易懂了。", |
| "<hr>", | ||
| "Use arrow function syntax to compute the square of only the positive integers (fractions are not integers) in the array <code>realNumberArray</code> and store the new array in the variable <code>squaredIntegers</code>." | ||
| "使用箭头函数的语法来计算 <code>squaredIntegers</code> 数组里正整数的平方（分数不是整数）" |
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正整数的平方（分数不是整数） => 正整数（注意，不包含小数）的平方
| "Check out this code:", | ||
| "<blockquote>function howMany(...args) {<br> return \"You have passed \" + args.length + \" arguments.\";<br>}<br>console.log(howMany(0, 1, 2)); // You have passed 3 arguments<br>console.log(howMany(\"string\", null, [1, 2, 3], { })); // You have passed 4 arguments.</blockquote>", | ||
| "The rest operator eliminates the need to check the <code>args</code> array and allows us to apply <code>map()</code>, <code>filter()</code> and <code>reduce()</code> on the parameters array.", | ||
| "ES6 推出了用于函数参数的<dfn>rest 操作符</dfn> 帮助我们创建更加灵活的函数。 在 <code>rest</code> 操作符的帮助下,你可以创建有一个变量来接受多个参数的函数。 这些参数被储存在一个可以在函数内部读取的数组中。", |
| "<hr>", | ||
| "Use destructuring to obtain the length of the input string <code>str</code>, and assign the length to <code>len</code> in line." | ||
| "使用解构语法去得到输入的 <code>str</code> 字符串的长度，并将长度赋值给 <code>len</code>。" |
| @@ -677,21 +677,21 @@ | |||
| "id": "587d7b89367417b2b2512b4a", | |||
| "title": "Use Destructuring Assignment to Assign Variables from Nested Objects", | |||
| "description": [ | |||
| "We can similarly destructure <em>nested</em> objects into variables.", | |||
| "Consider the following code:", | |||
| "同样，我们可以将 <em>嵌套的对象</em>解构到变量中。", | |||
| "<blockquote>const a = {<br> start: { x: 5, y: 6},<br> end: { x: 6, y: -9 }<br>};<br>const { start : { x: startX, y: startY }} = a;<br>console.log(startX, startY); // 5, 6</blockquote>", | ||
| "In the example above, the variable <code>start</code> is assigned the value of <code>a.start</code>, which is also an object.", | ||
| "在上面的例子里，<code>a.start</code> 将值赋给了变量 <code>start</code>，<code>start</code> 同样也是个对象。", |
| "<hr>", | ||
| "Use destructuring assignment to obtain <code>max</code> of <code>forecast.tomorrow</code> and assign it to <code>maxOfTomorrow</code>." | ||
| "使用解构赋值来得到 <code>forecast.tomorrow</code> 的 <code>max</code>，并将其赋值给 <code>maxOfTomorrow</code>。" |
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得到 => 获取
<code>forecast.tomorrow</code> 的 <code>max</code> 建议 =>
<code>forecast.tomorrow</code>的<code>max</code>属性对应的值
| ], | ||
| "tests": [ | ||
| { | ||
| "text": "<code>maxOfTomorrow</code> equals <code>84.6</code>", | ||
| "testString": "assert(getMaxOfTmrw(LOCAL_FORECAST) === 84.6, '<code>maxOfTomorrow</code> equals <code>84.6</code>');" | ||
| "text": "<code>maxOfTomorrow</code> 等于 <code>84.6</code>", |
S1ngS1ng
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huluoyang
suggested changes
Aug 2, 2018
| "<blockquote>var camper = 'James';<br>var camper = 'David';<br>console.log(camper);<br>// 打印出 'David'</blockquote>", | ||
| "在上面的代码中， <code>camper</code> 的初始值为 <code>'James'</code>，然后又被覆盖成了 <code>'David'</code>。", | ||
| "在小型的应用中，你可能不会遇到这样的问题，但是当你的代码规模变得更加庞大的时候，就可能会在不经意间覆盖了之前定义的变量。", | ||
| "这样的行为不会报错导致了 debug 非常困难。<br>", |
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因为这样的行为不会抛出异常，导致查找和修复 bug 变得很困难。
| "However, it is important to understand that objects (including arrays and functions) assigned to a variable using <code>const</code> are still mutable. Using the <code>const</code> declaration only prevents reassignment of the variable identifier.", | ||
| "<blockquote>\"use strict\";<br>const s = [5, 6, 7];<br>s = [1, 2, 3]; // throws error, trying to assign a const<br>s[2] = 45; // works just as it would with an array declared with var or let<br>console.log(s); // returns [5, 6, 45]</blockquote>", | ||
| "As you can see, you can mutate the object <code>[5, 6, 7]</code> itself and the variable <code>s</code> will still point to the altered array <code>[5, 6, 45]</code>. Like all arrays, the array elements in <code>s</code> are mutable, but because <code>const</code> was used, you cannot use the variable identifier <code>s</code> to point to a different array using the assignment operator.", | ||
| "在现代的 JavaScript 里，<code>const</code> 声明有很多用法", |
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在 JavaScript 的最新版本中，用 const 来声明变量有很多好处。
| "<blockquote>\"use strict\";<br>const s = [5, 6, 7];<br>s = [1, 2, 3]; // throws error, trying to assign a const<br>s[2] = 45; // works just as it would with an array declared with var or let<br>console.log(s); // returns [5, 6, 45]</blockquote>", | ||
| "As you can see, you can mutate the object <code>[5, 6, 7]</code> itself and the variable <code>s</code> will still point to the altered array <code>[5, 6, 45]</code>. Like all arrays, the array elements in <code>s</code> are mutable, but because <code>const</code> was used, you cannot use the variable identifier <code>s</code> to point to a different array using the assignment operator.", | ||
| "在现代的 JavaScript 里，<code>const</code> 声明有很多用法", | ||
| "一些开发者倾向默认使用 <code>const</code> 来声明所有变量，除非在他们知道需要更改某个变量的值的时候，才会使用 <code>let</code>", |
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开发者优先使用 const 来声明变量，只有当他们确定变量会被重新赋值，他们才会使用 let。
| "It's time we see how powerful arrow functions are when processing data.", | ||
| "Arrow functions work really well with higher order functions, such as <code>map()</code>, <code>filter()</code>, and <code>reduce()</code>, that take other functions as arguments for processing collections of data.", | ||
| "Read the following code:", | ||
| "我们已经见识到了箭头函数在处理数据时候的强大之处。", |
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曲解原意
这样翻译会不会更友好：是时候展现箭头函数的真正魅力了。
| "We can do something similar with objects as well. <dfn>Destructuring assignment</dfn> is special syntax for neatly assigning values taken directly from an object to variables.", | ||
| "Consider the following ES5 code:", | ||
| "我们之前看到了展开操作符是如何展开数组的内容的。", | ||
| "我们队对象也可以做同样的操作。 <dfn>解构赋值</dfn> 就是可以从对象中直接获取对应值的语法。", |
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同样的，解构赋值也可以直接从对象中获取值并赋给变量。
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新建了分支 PR 来解决 pull 后文件修改过多的问题。。。把原来的分支关了吧。。