[JS] Array() 생성자, Array.prototype.fill()

https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Array/Array

Array() 생성자

https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Array/fill

Array.prototype.fill()

틱택토 두번째 강좌에 나오고,, 자꾸 나와서 정리해봄 

 

 

 

Array()로 Array 생성

.fill(filling value, start position, end position)로 채움. 

[element0, element1, ..., elementN]

new Array(element0, element1[, ...[, elementN]])
new Array(arrayLength)

const array1 = [1, 2, 3, 4];

// fill with 0 from position 1 until position 3
console.log(Array(array1.length).fill(0, 1, 3));
// [undefined, 0, 0, undefined]

// fill with 5 from position 1
console.log(array1.fill(5, 1));
// expected output: [1, 5, 5, 5]

console.log(array1.fill(6));
// expected output: [6, 6, 6, 6]


console.log(Array(0))
// []
console.log(Array(2))
// [undefined, undefined]