[英]Is there syntactic sugar for calling a function on each element of a list in JavaScript?
Let's say I had the following code:假设我有以下代码:
let array = [1, 2, 3]
array.forEach(x => someFunc(x))
In Java, I know the second line could be simpler using Stream
s (at least for static methods), like so:在 Java 中,我知道第二行可以使用
Stream
更简单(至少对于静态方法),如下所示:
array.stream().map(ClassName::someFunc) ...
Essentially I'm asking is there an analog for the ClassName::someFunc
part in JavaScript, instead of having to write x => someFunc(x)
?本质上,我问的是 JavaScript 中的
ClassName::someFunc
部分是否有模拟,而不必编写x => someFunc(x)
?
Yes there is no need to wrap "someFunc" in an anonymous () =>
"arrow function"是的,不需要将“someFunc”包装在匿名
() =>
“箭头函数”中
As long as someFunc's first argument is configured to accept the currently iterated item from the array and do something with it then you can pass in a reference to that function as the argument in .forEach
(but do not call it).只要 someFunc 的第一个参数配置为从数组中接受当前迭代的项目并对其进行处理,那么您就可以传入对该函数的引用作为
.forEach
中的参数(但不要调用它)。
So you would do:所以你会这样做:
let array = [1, 2, 3]
array.forEach(someFunc)
Make sure not to do this:确保不要这样做:
let array = [1, 2, 3]
array.forEach(someFunc())
(note the calling parenthesis, this is bad) (注意调用括号,这很糟糕)
In the simplest case, you can replace在最简单的情况下,您可以替换
array.forEach(x => someFunc(x))
with just只需
array.forEach(someFunc)
but there's some fine print you should be aware of:但是您应该注意一些细则:
this generally doesn't work with object methods: .forEach(someObj.someMeth)
won't work这通常不适用于对象方法:
.forEach(someObj.someMeth)
不起作用
the callback should accept exactly one argument or conform to the forEach
calling convention callback(element, index, this)
.回调应该只接受一个参数或符合
forEach
调用约定callback(element, index, this)
。 For example, array.map(parseInt)
won't work either, because parseInt
has its own idea of what the second argument means.例如,
array.map(parseInt)
也不起作用,因为parseInt
对第二个参数的含义有自己的想法。
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