Efficient way to create and fill an array with consecutive numbers in range

问题

for the moment i use this JavaScript to create an array with n numbers from 0 to n

// javascript populate array 
var n=1000;
var arr=[n];
for (i=n;i>=0;i--) {
arr[i]=i;
console.log(arr[i]);
} 

is it the fast/right way to do the task?

回答1:

You can do declarative approach while using Array.from like this:

arr = Array.from({length: 20}, (e, i)=> i)
console.log(arr)

回答2:

An ES6 way of doing it using Array.keys():

let n = 10;
let arr = Array.from(Array(n).keys());

console.log(arr);

---

Made a quick JSPerf with answer so far:

https://jsperf.com/array-filling-so/

回答3:

You can use the function map skipping the first param of the predicate and getting the index i.

let arr = Array(10).fill().map((_, i) => i);
console.log(arr);

回答4:

The shortest way (I think) [...Array(10)].map((a,b)=>b)

console.log(
  [...Array(10)].map((a,b)=>b)
)

来源：https://stackoverflow.com/questions/55579499/efficient-way-to-create-and-fill-an-array-with-consecutive-numbers-in-range