time-hash

timehash
========

About
-----

> timehash is an algorithm (with multiple reference implementations) for calculating variable precision sliding windows of time. When performing aggregations and correlations on large-scale data sets, the ability to convert precise time values into 'malleable intervals' allows for many novel analytics.

> Using sliding windows of time is a common practice in data analysis but prior to the timehash algorithm it was more of an art than a science. -- abeusher/timehash

Installation
------------

npm install time-hash -s

npm install

npm run:cover

Usage
-------------


$3

> Improved browser compatability in Rollup

$3

`
timehash.encodems(new Date().getTime()) // encodes from milliseconds epoch instead of timeseconds
timehash.decodems('000000000b') // decodes to milliseconds epoch instead of timeseconds
`
> reason: Better compatability with Javascript Date() functions

$3

`
var TimeHash = require('time-hash') // or import TimeHash from 'time-hash'

let timehash = new TimeHash()

let [begin, cease] = ['1970-01-01 00:00:00 GMT', '2098-01-01 00:00:00 GMT'] // should use UTC/GMT

let begin_input = new Date(begin)
let pivot_input = new Date('2034-01-01 00:00:00 GMT')
let cease_input = new Date(cease)

let begin_hash = timehash.encode_from_datetime(begin_input)
let pivot_hash = timehash.encode_from_datetime(pivot_input)
let cease_hash = timehash.encode_from_datetime(cease_input)

${begin_hash}
'0000000000'

${pivot_hash}
'bfffffffff'

${cease_hash}
'ffffffffff'

begin_hash_after = timehash.after(begin_hash)
${begin_hash_after}
'0000000001'
${timehash.before(begin_hash_after)} === begin_hash

let [neighbor_before, neighbor_after] = timehash.neighbors('000000000a')
${timehash.before(neighbor_before)} === begin_hash
${neighbor_after} === '000000000b'

let input = '000000000a'
let expand = timehash.expand(input)
let [expand_before, input_clone, expand_after] = expand
${expand_before} === timehash.before(input_clone)
${expand_after} === timehash.after(input_clone)

let [begin_value, begin_error] = timehash.decode_exactly('0000000000')
new Date(begin_value - begin_error).toString() === begin_input.toString()

``

Other Compatible Implementations
---------------

- python timehash
- a reference implementation in pure python
- perl timehash
- a reference implementation in perl
- java timehash
- a reference implementation in java

$3

Copyright © 2017 LoreFolk, LLC. This source code is licensed under the MIT license found in
the LICENSE.txt file.
The documentation to the project is licensed under the CC BY-SA 4.0
license.

---
Reference implement made with ♥ by Abe Usher Abe Usher and [contributors] (https://github.com/abeusher/timehash/blob/master/CONTRIBUTORS.md)

Testing/DepoymentTemplate made with ♥ by Konstantin Tarkus (@koistya) and contributors