unique-random
Generate random numbers that are consecutively unique or exhaustively unique within a range.
What is unique-random?
Unique-random is a JavaScript library that generates random numbers with specific uniqueness constraints. It solves the problem of needing random sequences where values don't repeat consecutively or until all possibilities are exhausted, which is useful for slideshows, games, or any application where immediate repeats are undesirable.
JavaScript developers building applications that require controlled random sequences, such as slideshow presentations, game mechanics, or data sampling tools.
Developers choose unique-random for its simple API, clear uniqueness guarantees, and iterable interface, which provide more control over random number generation than standard Math.random() without complex manual implementations.
Overview
Generate random numbers that are consecutively unique
Use Cases
Best For
- Creating slideshows that never show the same slide twice in a row
- Implementing game mechanics where consecutive random events must differ
- Generating unique test data samples without immediate duplicates
- Building media players with shuffle modes that avoid back-to-back repeats
- Developing lottery or drawing systems with controlled randomness
- Creating randomized UI elements that shouldn't repeat consecutively
Not Ideal For
- Applications requiring cryptographically secure random number generation
- Projects needing reproducible random sequences with seeding for testing
- Scenarios where floating-point random numbers are necessary instead of integers
Pros & Cons
Pros
Functions like consecutiveUniqueRandom(min, max) require only two parameters, making integration straightforward, as shown in the basic usage example.
The returned random function is also an iterable, allowing direct use in for...of loops for infinite sequences, demonstrated in the README's iteration example.
Offers two specific modes—consecutive and exhaustive—that prevent back-to-back repeats or ensure full range coverage, ideal for slideshows and games mentioned in the description.
Part of a family of sindresorhus utilities, with related projects like unique-random-array for array-based randomness, enhancing utility for developers.
Cons
Lacks the ability to seed the random number generator, making it unsuitable for deterministic testing or scenarios requiring reproducible sequences.
Restricted to integer generation within min/max bounds; for floating-point numbers, developers must use separate libraries like random-float, as indicated in related projects.
In exhaustiveUniqueRandom mode, tracking used numbers to ensure no repeats until exhaustion can be memory-intensive for large ranges, a trade-off for the uniqueness guarantee.
Frequently Asked Questions
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