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https://github.com/hackergrrl/hyper-string
conflict-free p2p string data structure powered by a hyperlog of operations
https://github.com/hackergrrl/hyper-string
Last synced: 12 days ago
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conflict-free p2p string data structure powered by a hyperlog of operations
- Host: GitHub
- URL: https://github.com/hackergrrl/hyper-string
- Owner: hackergrrl
- Created: 2016-06-24T20:04:59.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2018-02-02T06:17:15.000Z (almost 7 years ago)
- Last Synced: 2024-05-21T01:04:58.292Z (6 months ago)
- Language: JavaScript
- Homepage:
- Size: 45.9 KB
- Stars: 38
- Watchers: 5
- Forks: 6
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
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- awesome-peer-to-peer - hyper-string - free string primitive (Modules)
README
# hyper-string
> conflict-free p2p string data structure powered by a hyperlog of operations
**STATUS**: very mad science-y work-in-progres
**TODO**: write some background / context on this. talk about the implications
of representing a textual string as an append-only log of operations, with a
materialized view as a DAG of character sequences.
## Usage
Let's start writing "Helo", but have a fork where some other user wants to
fix the spelling error by inserting another "l".
```js
var hstring = require('hyper-string')
var memdb = require('memdb')
var str = hstring(memdb())
str.insert(null, null, 'Hola', function (err, ops) {
// ops is an array of four unique IDs
str.insert(null, ops[0], '¡')
str.insert(ops[ops.length-1], null, '!')
})
str.text(function (err, text) {
console.log(text)
})
```
This will output
```
¡Hola!
```
## API
```js
var hstring = require('hyper-string')
```
### var str = hstring(db, opts={})
Creates a new hyper-string, backed by the
[LevelUP](https://github.com/Level/levelup) instance `db`.
### str.insert(beforePos, afterPos, string, [cb])
Inserts all characters of `string` after position `beforePos` and before
position `afterPos`, which are unique IDs of other characters previously
inserted. If 'beforePos` is `null`, the given string is inserted at the
beginning of the hyper-string. If `afterPos` is `null`, it is inserted at the
end.
Remember, since the hyper-string is represented by a directed acyclic graph, it
can have many different "beginnings" and "ends". hyper-string ensures that the
ordering of these are deterministic.
The callback `cb` is called with the signature `function (err, chars)`, where
`chars` is an array of the inserted characters of the form
```js
{
chr: 'P',
pos: '...'
}
```
### str.delete(from, to, [cb])
Deletes the characters between positions `from` and `to`, inclusive. `cb` is
called with the signature `function (err)`.
```js
{
op: 'delete',
from: '...',
to: '...'
}
```
### str.text(cb)
Asynchronously returns a string, in the order they would be displayed for a
human to read.
### str.chars(cb)
Asynchronously returns all characters in the string, in the order they would be
displayed for a human to read. Each object is of the form
```js
{
chr: 'P',
pos: '...'
}
```
## Install
With [npm](https://npmjs.org/) installed, run
```
$ npm install hyper-string
```
## Acknowledgments
Based on the [Logroot CRDT
paper](https://hal.archives-ouvertes.fr/file/index/docid/345911/filename/main.pdf)
by Stephane Weiss, Pascal Urso, and Pascal Molli.
## License
ISC