js fill()
[JS Array from()](https://texonom.com/js-array-from-4eed5c3d3a1846cd9d17ad692b942b43) 


### To init js array
```typear = new Array(n).fill(0)```






> [Array.prototype.fill()](https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Array/fill)






```typeArray.from({length: 4})```