paralleldrive/cuid
Cuid
Cuid is a JavaScript library that generates collision-resistant unique identifiers. Each id is built from a timestamp, a counter, a machine fingerprint, and random blocks, so records can be created on many servers and browsers without a central coordinator. Generation is synchronous and local, which lets a client build a complete record and insert it without asking the database to assign a key. The repository also documents the id format as a specification, and it is marked as deprecated: the format leaks timestamps and is considered insecure, so a newer successor is recommended instead.
The ids begin with a fixed letter and use only lowercase base-36 characters, so they work directly as HTML element ids and in URLs. Because values increase roughly with creation time, they are suited to sortable database primary keys. The library also offers a short slug function that returns seven to ten characters for disambiguating URLs. Slugs trade uniqueness and unguessability for brevity, so they should not be used as database keys or to protect private resources. A validation helper checks whether a string is a well-formed full id or a slug.
The same code runs in Node, browsers, and mobile runtimes. The build ships a server module and a minified browser bundle, and swaps in environment-specific sources for the fingerprint and random values. The fingerprint method can be overridden, and the algorithm can be reimplemented in other languages and on other platforms while keeping the same id format.
Continuous integration runs the test suite across several Node versions and in real Chrome and Firefox under a virtual display. A dependency update bot is configured to merge minor updates automatically and hold major-version bumps for manual review.
