我有一个关于.map 的问题，将数组中的元素带入带有 javascript 的数组中

Question

I am currently trying to bring the elements in an array into other arrays in the array. I have now read that .map works well and have found newArrayA as an example. Can't I just leave out the dots and just do it as in newArrayB ? Does anyone have anything else to read? I can find almost nothing on this example. Is there anything that speaks against newArrayB ?

 let test = ['A', 'B', 'C', 'D']; // to [ [ 'A' ], [ 'B' ], [ 'C' ], [ 'D' ] ] newArrayA = test.map((x) => [...x]); newArrayB = test.map((x) => [x]); console.log(newArrayA); console.log(newArrayB);

Answer 1

You can see the difference by increasing the length of one of the strings - you get different results when you use the spread operator vs simply using the value at an index - just run this example:

 let test = ['ABCDE', 'B']; newArrayA = test.map((x) => [...x]); newArrayB = test.map((x) => [x]); console.log(newArrayA); console.log(newArrayB);