Fractional Indexing
This is based on Implementing Fractional Indexing by David Greenspan .
Fractional indexing is a technique to create an ordering that can be used for Realtime Editing of Ordered Sequences.
This implementation includes variable-length integers, and the prepend/append optimization described in David's article.
Usage
import { generateKeyBetween } from 'fractional-indexing';
const first = generateKeyBetween(null, null); // "a0"
// Insert after 1st
const second = generateKeyBetween(first, null); // "a1"
// Insert after 2nd
const third = generateKeyBetween(second, null); // "a2"
// Insert before 1st
const zeroth = generateKeyBetween(null, first); // "Zz"
// Insert in between 2nd and 3rd. Midpoint
const secondAndHalf = generateKeyBetween(second, third); // "a1V"Other Languages
These should be byte-for-byte compatible.
| Language | Repo |
|---|---|
| Go | https://github.com/rocicorp/fracdex |
| Python | https://github.com/httpie/fractional-indexing-python |