如何用条件进行对象解构？

Question

So I have:

// some function that returns two arrays ..
getArrays() {
  return {
    arr1: [...],
    arr2: [...]
  };
}

// and then ..
let arr1 = [];
let arr2 = [];
if (someCondition) {
  { arr1, arr2 } = getArrays();
}

// here we expect arrays, even if they are empty ..

Of course, this throws an error. Is this even possible?

PS: I can use default values and directly call the function, but still - I think it should be possible.

Answer 1

One solution is to wrap the destructuring expression with parentheses:

 // some function that returns two arrays .. function getArrays() { return { arr1: [1], arr2: [2] }; } const someCondition = true; let arr1 = []; let arr2 = []; if (someCondition) { ({ arr1, arr2 } = getArrays()); } console.log(arr1, arr2); 

Another solution is to move the condition to the getArrays() function, and if the condition is false return two empty arrays:

 const getArrays = (condition) => condition ? { arr1: [1], arr2: [2] } : { arr1: [], arr2: [] }; const someCondition = true; const { arr1, arr2 } = getArrays(someCondition); console.log(arr1, arr2); 

You can also use the condition and ternary outside of the function:

 const getArrays = () => ({ arr1: [1], arr2: [2] }); const someCondition = true; const { arr1, arr2 } = someCondition ? getArrays() : { arr1: [], arr2: [] }; console.log(arr1, arr2);