使用默认值和三元运算符查找的可选链接方法

Question

i am trying to implement the optional chaining in array.find. see the below snippet code i have below three cases

1. if array is empty i need to have the true // by default true
2. if the array didn't find the object it should also be true // empty as true value
3. if the array has the object it should take the key property value // true or false

But as per the 3 case, if the key value is false its taking the 2 one

 let array = [{ id: 1, key: false }, { id: 2, key: true }] let key = array && array.length? array.find( (item) => item.id === 1 )?.key || "empty as true value": "by default true"; console.log(key)

Answer 1

You cannot use || when the left-hand side value can be falsy. You will either need to use it on the object (which is truthy) before accessing the .key

const key = (array?.find(item =>
  item.id === 1
) || {key: "empty as true value"}).key;

or better use the nullish coalescing operator :

const key = array?.find(item =>
  item.id === 1
)?.key ?? "empty as true value";