// Array.from에 length만 존재하는 유사 배열 객체를 전달하면 undefined를 요소로 채운다
const arr8 = Array.from({ length: 3 });
console.log(arr8);
console.log(Object.getOwnPropertyDescriptors(arr8));
/*
{
'0': {
value: undefined,
writable: true,
enumerable: true,
configurable: true
},
'1': {
value: undefined,
writable: true,
enumerable: true,
configurable: true
},
'2': {
value: undefined,
writable: true,
enumerable: true,
configurable: true
},
length: { value: 3, writable: true, enumerable: false, configurable: false }
}
*/
const arr9 = [];
arr9.length = 3;
console.log(arr9);
console.log(Object.getOwnPropertyDescriptors(arr9));
/*
{
length: { value: 3, writable: true, enumerable: false, configurable: false }
}
*/
const arr10 = [, , ,];
console.log(arr10);
console.log(Object.getOwnPropertyDescriptors(arr10));
/*
{
length: { value: 3, writable: true, enumerable: false, configurable: false }
}
*/
const arr11 = new Array(3);
console.log(arr11);
console.log(Object.getOwnPropertyDescriptors(arr11));
/*
{
length: { value: 3, writable: true, enumerable: false, configurable: false }
}
*/
JavaScript
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