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

Version 1.2.0 Update

Improved browser compatability in Rollup

Version 1.1.1 Update

    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

Version 1.0

    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

License

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.

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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