Javascript语法[]（）和（）（） [英] Javascript syntax []() and ()()

问题描述

我无法理解这些JavaScript语法。在下面的代码块中，在第二行。方括号后面是一个圆括号或括号，我怀疑是用来得到论据。我不明白这两个是如何被链接形成一个表达方式，它是什么意思。

I'm having trouble understanding these javascript syntaxes. In the block of code below, on the second line. The square bracket is quickly followed by a round bracket or parentheses which I suspected is used to get arguments. I do not understand how this two is being chained to form an expression and what it means.

 export const recipeCount = createReducer(0, {
      [types.ADD_RECIPE](state, action){
        return state + 1;
      }
    });

同样在这一行上，connect方法有两个参数，（state ）=> {return {}} 和 mapDispatchToProps 。然后用（）和参数快速地回覆。起初，我虽然是java中的一些对象转换，但是没有意义。

Also on this line, the connect method takes in two arguments, (state) => {return {}} and mapDispatchToProps . Then it is quickly follwed by () with an argument. At first, i though it was some of object casting in java but that doesn't make sense.

export default connect((state) => {return {}}, mapDispatchToProps)(AppContainer);

代码执行正常并产生预期结果。我只是不明白发生了什么。请帮助，很高兴得到答案，伴随着我可以阅读的页面的链接，以便更好地了解。谢谢。

The code executes fine and produces expected result. I just don't understand what is going on. Pls Help, would be glad to get answersre accompanied with links to pages i can read for better understanding. Thanks.

推荐答案

答案在评论的问题。不得不再次将它们复制出来，所以我可以将问题标记为已回答并关闭它。

Answers are in the comment to the question. Had to copy them out again, so i can mark the question as answered and close it.

不知道第一个发生了什么，第二个， connect（）是一个返回函数的函数，所以second（）是立即调用返回的函数。 - Ouroborus

"Not sure what's going on with the first one. For the second one, connect() is a function that returns a function so the second () is to immediately call that returned function." – Ouroborus

第一个是一个动态对象文字属性，也是一个对象方法，我发现这是不可读的，我会重写一个。 - Davin Tryon

"The first one is a dynamic object literal property that is also an object method. I find this not readable at all. I would re-write that one. – Davin Tryon"

以及计算的属性名称以使其更清楚 - DenysSéguret

and also a link to Computed property names to make it clearer from – Denys Séguret

感谢贵司。

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