可以使用数组中的扩展运算符和 JavaScript 中的 object 找出差异

Question

I am using spread operator in an array like below:

 const addOne = false; const arr = [1, 2, 3] const arr1 = [...arr, ...(addOne && [8, 9])]; console.log(arr1)

And I got the error

TypeError: (addOne && [8,9]) is not iterable
    at <anonymous>:4:32

While if I use spread operator in an object like:

 const addOne = false; const obj = { name: 'peter', age: 23 } const obj1 = {...obj, ...(addOne && obj) } console.log(obj1)

it prints out the correct output

Anyone knows why?

Answer 1

(false && obj) evaluates to a boolean so its' not iterable.
When using the spread operator when building your obj1 object, js uses a different method to extract the key value pairs from an object (remember that a bool value in js is still an object), so it won't throw an error since it's expecting an object as an input.