Javascript 如何使用 ES6 Fat Arrow 来 .filter() 对象数组
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/32040396/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to use ES6 Fat Arrow to .filter() an array of objects
提问by Henry Zhu
I'm trying to use ES6 arrow function with .filterto return adults (Hyman & Jill). It appears I cannot use an if statement.
我正在尝试使用 ES6 箭头函数.filter返回成人（Hyman & Jill）。看来我不能使用 if 语句。
What do I need to know in order to do this in ES6?
为了在 ES6 中做到这一点，我需要知道什么？
var family = [{"name":"Hyman", "age": 26},
{"name":"Jill", "age": 22},
{"name":"James", "age": 5 },
{"name":"Jenny", "age": 2 }];
let adults = family.filter(person => if (person.age > 18) person); // throws error
(8:37) SyntaxError: unknown: Unexpected token (8:37)
|let adults = family.filter(person => if (person.age > 18) person);
My working ES5 example:
我的工作 ES5 示例：
let adults2 = family.filter(function (person) {
if (person.age > 18) { return person; }
});
回答by Felix Kling
It appears I cannot use an if statement.
看来我不能使用 if 语句。
Arrow functions either allow to use an expressionora blockas their body. Passing an expression
箭头功能或者允许使用一个表达式或一块作为他们的身体。传递表达式
foo => bar
is equivalent to the following block
相当于下面的块
foo => { return bar; }
However,
然而，
if (person.age > 18) person
is not an expression, ifis a statement. Hence you would have to use a block, if you wanted to use ifin an arrow function:
不是表达式，if是语句。因此，如果要if在箭头函数中使用，则必须使用块：
foo => { if (person.age > 18) return person; }
While that technically solves the problem, this a confusing use of .filter, because it suggests that you have to return the value that should be contained in the output array. However, the callback passed to .filtershould return a Boolean, i.e. trueor false, indicating whether the element should be included in the new array or not.
虽然这在技术上解决了问题，但这是一个令人困惑的用法.filter，因为它表明您必须返回应该包含在输出数组中的值。但是，传递给的回调.filter应该返回一个Boolean，即trueor false，指示该元素是否应包含在新数组中。
So all you need is
所以你只需要
family.filter(person => person.age > 18);
In ES5:
在 ES5 中：
family.filter(function (person) {
return person.age > 18;
});
回答by Kit Sunde
You can't implicitly return with an if, you would need the braces:
你不能用 an 隐式返回if，你需要大括号：
let adults = family.filter(person => { if (person.age > 18) return person} );
It can be simplified though:
不过可以简化一下：
let adults = family.filter(person => person.age > 18);
回答by Mo.
As simple as you can use const adults = family.filter(({ age }) => age > 18 );
尽可能简单地使用 const adults = family.filter(({ age }) => age > 18 );
const family =[{"name":"Hyman", "age": 26},
{"name":"Jill", "age": 22},
{"name":"James", "age": 5 },
{"name":"Jenny", "age": 2 }];
const adults = family.filter(({ age }) => age > 18 );
console.log(adults)回答by Sabri Mevi?
Here is my solution for those who use hook; If you are listing items in your grid and want to remove the selected item, you can use this solution.
这是我为那些使用的人的解决方案hook；如果您在网格中列出项目并希望删除所选项目，则可以使用此解决方案。
var list = data.filter(form => form.id !== selectedRowDataId);
setData(list);
