app.mjs:

import uniqueRandom from 'unique-random';

const random = uniqueRandom(1, 5);

console.log(random(), random(), random());

results:

PS D:\app\node-demo> node app.mjs
3 5 2
PS D:\app\node-demo> node app.mjs
4 1 5
PS D:\app\node-demo> node app.mjs
5 3 2
PS D:\app\node-demo> node app.mjs
2 1 2
PS D:\app\node-demo> node app.mjs
3 2 1
PS D:\app\node-demo> node app.mjs
4 1 2
PS D:\app\node-demo> node app.mjs
4 5 4

Currently unique-random only guarantees a unique random value at a depth of 1 in the call history. We can potentially add a third optional argument depth where users can specifiy how many calls deep the returned value should be compared against. So something like

var rand = uniqueRandom(1, 10, 3);

would mean that the returned value would be unique relative to the last 3 calls.

I'm just wondering if this is something you'd be interested in supporting. If so I can PR. I can fork it otherwise.

... would be a nice lib to have.

Just installed the package, cool idea BTW!
Unfortunately I think it's not working correctly.
the following code:

import uniqueRandom from "unique-random";

const random = uniqueRandom(1, 4);
console.log(random(), random(), random(), random());

sometimes has bad results (i.e 1, 2, 4, 2 or 4, 1, 3, 4). I've noticed it's never the same number twice in a row if that's helpfull.

I was reviewing this function's code, and was surprised by how dense it was written. Just curious if you still support this style of code. (2 and a half years is 20-20?)

Admittedly it is perfectly effective, just far from readable. Like this line:

return prev = num === prev && min !== max ? rand() : num;

😄

(theoretically) If they are equal then the previous value will always be the same, so the program enters an infinite loop.

I think it is a better fix to make it work with only one number anyways, as opposed to throwing an error since this could happen if min and max are generated by another source.

Heya. I haven't been much active for a long time.

Just tired that package and.. man, several runs and always get a duplicates.

const random = uniqueRandom(1, 100);

console.log(
    Array(30)
        .fill(0)
        .map(() => random())
        .sort((a, b) => a - b)
);

outputs

[
   1,  7,   7, 10, 11, 12, 13, 24, 27,
  38, 39,  41, 43, 47, 51, 52, 59, 62,
  66, 67,  68, 70, 72, 82, 82, 84, 85,
  94, 99, 100
]

this one is not sorted, but at least the 83 is repeated.

[
  41, 16, 61,  2, 30, 56, 71, 20, 24,
  53, 73, 47, 23, 68, 14, 83, 47, 13,
  77, 16, 59, 43, 80, 79, 83, 30, 52,
  12, 97,  7
]

Am I that unlucky or what? 😆

Maybe a better way would be the previousValue to be something like temp array instead and lookup on it.

How we can using it in for loop?

This can be useful, for example, for a music shuffle functionality. It should also ensure numbers across boundaries don't overlap. This would also be useful for slideshows to ensure the images don't show like "image A, image F, image A, …".