# Is there any suggestion around adding inclusive / exclusive ranges descriptors in JavaScript
**URL:** https://es.discourse.group/t/is-there-any-suggestion-around-adding-inclusive-exclusive-ranges-descriptors-in-javascript/640
**Category:** 💡 Ideas
**Tags:** proposal
**Created:** [February 7, 2021, 3:24am UTC](https://es.discourse.group/t/is-there-any-suggestion-around-adding-inclusive-exclusive-ranges-descriptors-in-javascript/640 "2021-02-07T03:24:23Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@aleen42](https://es.discourse.group/u/aleen42)
#### Post date: [February 7, 2021, 3:24am UTC](https://es.discourse.group/t/is-there-any-suggestion-around-adding-inclusive-exclusive-ranges-descriptors-in-javascript/640/1 "2021-02-07T03:24:23Z")
```javascript
m..n (exclusive)
m..=n (inclusive)
```
For instance, `1..3` means for `[1, 2]`, while `1..=3` means for `[1, 2, 3]`:
```javascript
for (const val of 1..3) console.log(val); // => 1, 2
for (const val of 1..=3) console.log(val); // => 1, 2, 3
```
### References:
- [Inclusive Ranges in Rust](https://doc.rust-lang.org/edition-guide/rust-2018/data-types/inclusive-ranges.html)
---
### Author:  [@aaditmshah](https://es.discourse.group/u/aaditmshah)
#### Post date: [February 7, 2021, 4:21am UTC](https://es.discourse.group/t/is-there-any-suggestion-around-adding-inclusive-exclusive-ranges-descriptors-in-javascript/640/2 "2021-02-07T04:21:45Z")
We already have a [GitHub - tc39/proposal-Number.range: A proposal for ECMAScript to add a built-in Number.range()](https://github.com/tc39/proposal-Number.range) proposal which allows for both inclusive and exclusive ranges.
Not sure whether having syntactic sugar for `Number.range` would be necessary. I'm also assuming that you'd want syntactic sugar for `BigInt.range` too. For example, `1n..3n` and `1n..=3n` for exclusive and inclusive ranges respectively.
Also note that `1..3` could be interpreted as a property access. For example, `1..toString()` is valid JavaScript. The literal is `1.` and the `.toString()` is the method invocation. Hence, this syntax might be confusing.
Next, what if I want to generate a sequence with a step other than `1`? For example, if I want to generate the sequence `0,2,4,6,8` or the sequence `5,4,3,2,1`? What should be the syntax for such sequences?
Finally, would it make sense for the syntactic sugar to create an iterator or should it create an array? That is should `1..3` evaluate to `[1,2]` or should it evaluate to `Number.range(1, 3)`? The latter of course being an iterator. That way, we can create infinite sequences without having to allocate space.
If we explicitly want an array then we could have `[1..3]`. Similarly, if we wanted a set we could have `new Set(1..3)`. Would this be more desirable?
---
### Author:  [@aleen42](https://es.discourse.group/u/aleen42)
#### Post date: [February 23, 2021, 3:44am UTC](https://es.discourse.group/t/is-there-any-suggestion-around-adding-inclusive-exclusive-ranges-descriptors-in-javascript/640/3 "2021-02-23T03:44:16Z")
To some extent, a syntactic sugar like this should make the code more simple to read.
When it comes to how to generate a reversed sequence like `5, 4, 3, 2, 1`, we can define the order as sensitive order between `m` and `n`, and `5..=1` is not equivalent to `1..=5`.
Step of a sequence is not an often case, and we can ignore it. For me, I intend to consider whether such a sugar should be limited to a sub-sequence of natural numbers.