使用node js匹配数组

Question

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let arr= ["Product",["car","Bike"]];
let out= arr[1].map((rest)=>[arr[0],rest]);
console.log(out);

​

所以我得到的输出是

[[Product , car],
 [Product , bike]],

我可以用上面的代码做到这一点，因为我的输出很简单，但我不知道如何做这个输出

[["product",["car","Bike","truck"]],
 ["Milk",["cheese","butter","curd"]],
 ["Animals",["Lion","Tiger"]]]

因为我在此输出上尝试了相同的代码，但得到了以下代码

​

let arr= [["product",["car","Bike","truck"]],
 ["Milk",["cheese","butter","curd"]],
 ["Animals",["Lion","Tiger"]]];
 let out= arr[1].map((rest)=>[arr[0],rest]);
 console.log(out);

​

因为我的预期输出如下所示：

[Product car]
[Product bike]
[Product truck]
[Milk cheese]
[Milk butter]
[Milk curd]
[Animal Lion]
[Animal Tiger]

我有没有可能像期望的输出那样把每个对象分开？不是这样的

[[Product car]
 [Product bike]
 [Product truck]
 [Milk cheese]
 [Milk butter]
 [Milk curd]
 [Animal Lion]
 [Animal Tiger]]

Answer 1

这将为您提供所需的最终数组。

let arr= [["product",["car","Bike","truck"]],
     ["Milk",["cheese","butter","curd"]],
     ["Animals",["Lion","Tiger"]]];

 let array =[];

 for(let i = 0;i<arr.length;i++){
        let out = arr[i][1].map(rest =>[arr[i][0],rest])
        array.push(out)
 }

Answer 2

你需要嵌套循环。内部循环类似于原始的map()，外部循环可以使用flatMap()来连接内部循环的结果。

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let arr = [
  ["product", ["car", "Bike", "truck"]],
  ["Milk", ["cheese", "butter", "curd"]],
  ["Animals", ["Lion", "Tiger"]]
];
let out = arr.flatMap(([first, rest]) => rest.map(el => [first, el]));
console.log(out);

​