This is a browser JavaScript library for generating Universally Unique Lexicographically Sortable Identifiers (ULIDs). With modern browsers on modern hardware, it can generate 1.5 million ULIDs per second.

The API is a single constructor. It constructs a closure that generates monotonic ULIDs each time it's invoked.

let generator = ULID();
let ulid0 = generator();
let ulid1 = generator();
assert(ulid0 < ulid1);

The generator itself makes no allocations when generating ULIDs, except for the returned ULID string.