# hashlog

> HashLog is an experimental data structure

Latest version **1.0.1** (published 2016-02-25) · ISC license · 0 weekly downloads

## Install

```sh
npm install hashlog
pnpm add hashlog
yarn add hashlog
bun add hashlog
```

## Health

**Score 15/100 (F)** — status: abandoned.

Positive: no vulnerabilities.

Warnings: low downloads; no types; no esm support.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 1.0.1 |
| Published | 2016-02-25 |
| First published | 2016-02-25 |
| Weekly downloads | 0 |
| License | ISC |
| TypeScript types | none |
| Module format | CommonJS |
| Dependencies | 3 |
| Known vulnerabilities | 0 |
| Install scripts | no |
| Maintainers | asbjornenge |

## Links

- npm: https://www.npmjs.com/package/hashlog
- npm.io page: https://npm.io/package/hashlog

## Dependencies (3)

- [farmhash](https://npm.io/package/farmhash.md) ^1.1.0
- [node-uuid](https://npm.io/package/node-uuid.md) ^1.4.7
- [merkle-tree-stream](https://npm.io/package/merkle-tree-stream.md) ^1.0.2

## Recent versions

- 1.0.1 (latest) — 2016-02-25
- 1.0.0 — 2016-02-25

## README

# HashLog

HashLog is an experimental data structure using [merkle-style](https://en.wikipedia.org/wiki/Merkle_tree) hashing and a time-delta inspired by [lamport timestamp](https://en.wikipedia.org/wiki/Lamport_timestamps) to create a *commit-log* type structure that ensures correct ordering of commits on merge, even for distributed logs (unsynchronized clocks).

FYI: This is totally an experiment!

## Theory

By using merkle-style hashing we can prove the order of the commits to our log. On merge, if we can find a common hash in the past, we can be sure that all data up to this merge-point is the same for both logs. By also storing a time-delta between commits we can calculate deltas from the merge-point and ensure correct ordering of commits made to different logs.

Also; logs are great! You can build any other kind of data structure using a log.

## Install

```sh
npm install --save hashlog
```

## Use

```js
import HashLog   from 'hashlog'
import { merge } from 'hashlog/utils'

let log1 = new HashLog(['data1'])
let log2 = new HashLog(['data1'])

log1.push('data2')
merge(log1, log2) // Merge log2 into log1 
merge(log2, log1) // Merge log1 into log2
assert(log1.tip.chainhash == log2.tip.chainhash)
assert(log1.tip.value == log2.tip.value)
assert(log1.tip.value == 'data2')
```

## Benchmark

```sh
$ npm run bench 
mock: 581ms
init: 15043ms
push: 419ms
merge1: 606ms
merge2: 331ms
17869837359133814333 1050000 datr442t9
17869837359133814333 1050000 datr442t9
```

enjoy.

---
_Source: https://npm.io/package/hashlog · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._