Is there a way to create an Integer range?
In other languages, I can use Range(1, 9) to create [1, 2, ... 8] easily.
Is there a simple way to create the list in JavaScript?
- What is it you want to accomplish with a range if I may ask?Ron Nabuurs– Ron Nabuurs2018-05-07 13:46:51 +00:00Commented May 7, 2018 at 13:46
- See this question which has lots of different approaches: stackoverflow.com/questions/3746725/…Our_Benefactors– Our_Benefactors2018-05-07 13:47:12 +00:00Commented May 7, 2018 at 13:47
- npmjs.com/package/multi-integer-rangeSzellem– Szellem2018-05-07 13:50:23 +00:00Commented May 7, 2018 at 13:50
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3 Answers
const range = (start, end) => Array.from({length: end - start}, (_, i) => start + i); console.log(range(1,5)); That creates an array with the indexes. If you need it in a loop, an iterator might be better:
function* range(start, end = Infinity) { for(let i = start; i < end; i++) yield i; } Which can be used as:
for(const v of range(1, 10)) console.log(v); You can also turn an iterator into an array easily:
console.log([...range(0, 10)]); 
1 Comment
Ankit Agarwal
This will give error for Range(9,1). This case is also not handled
Is there a simple way to create the list in JavaScript?
No, but you can create your own solution using ES features like map and spread syntax.
var range = (start, end) => start < end ? [...Array(end - start)].map((_, i) => start + i) : []; console.log(range(1,9));Also, returns an empty array for case when start is greater than end.
answered May 7, 2018 at 13:47
Mihai Alexandru-Ionut
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6 Comments
Ankit Agarwal
OP needs 1-8 if input with
(1,9)
Mihai Alexandru-Ionut
@AnkitAgarwal, updated.
Ankit Agarwal
This will give error for
Range(9,1). This case is also not handledMihai Alexandru-Ionut
@AnkitAgarwal, for
start > end I returns just an empty array.Ankit Agarwal
Yes, it seems good now
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You can create a reusable function called Range and loop over the start and end values. You can further add a if condition that ensures that the start value is always less than the end value.
function Range(start, end){ var rangeArray = []; if(start < end){ for(var i=start; i<end; i++){ rangeArray.push(i); } } return rangeArray; }; console.log(Range(1,9)); console.log(Range(2,9)); console.log(Range(5,12)); console.log(Range(16,12)); console.log(Range(30,12));