bin-allocator

allocate values to bins defined by their lower bound delimitor value.

the ideal approach would have been to subclass Array and simply override the Array#indexOf method such that it returns the index of the closest delimitor below the given value, instead of returning the index of an exact match if any. however, this is problematic, especially in Typescript

instead, this module favors composition over inheritance, and currently exposes only three properties of the underlying array, which serve the purpose of allocating values to bins:

• Array#indexOf which is overridden with the previously described behaviour, implemented as binary search in O(n).
• Array.length (readonly)
• Array#map which effectively provides indirect access to the underlying array.

an optional comparator function can be given at instantiation.

example

import getBinAllocator from 'bin-allocator'
import getRandomBinsFactory from 'randombins'
import debug = require('debug')
const log = debug('example:')
debug.enable('example:')

// create bins, i.e. a list of randomly selected bin delimitor strings
const getRandomBins = getRandomBinsFactory({ size: 16 }) // no shuffle
const alphabet = '-abcdefghijklmnopqrstuvw_'
getRandomBins([ alphabet, alphabet ])
.reduce((bins , bin) => bins.concat(bin), <string[]>[])
.then(bins => {
  const orderedbins = getBinAllocator(bins)
  log('number of bins:', orderedbins.length) // 16
  log('delimitor strings:', orderedbins.map(s => s)) // e.g. ["--", "-p", "bd", ..., "ws"]

  const words = [ 'this', 'is', 'an', 'example' ]
  const map = words.reduce((map, word) => {
    map[word] = orderedbins.indexOf(word)
    return map
  }, {})

  log('words to corresponding bin index: %o', map) // e.g. { an: 1, example: 4, is: 6, this: 12 }
})

the files of this example are available here.

a live version of this example can be viewed here in the browser console, or by cloning this repository and running the following commands from a terminal:

npm install
npm run example

API v1.0 stable

ES5 and Typescript compatible. coded in Typescript 2, transpiled to ES5.

for a detailed specification of the API, run the unit tests in your browser.

CONTRIBUTING

see the contribution guidelines

LICENSE

Copyright 2017 Stéphane M. Catala

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and Limitations under the License.