https://github.com/javiercejudo/positional-notation

Calculate the decimal equivalent given a base, a position and a decimal value
https://github.com/javiercejudo/positional-notation

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Calculate the decimal equivalent given a base, a position and a decimal value

• Host: GitHub
• URL: https://github.com/javiercejudo/positional-notation
• Owner: javiercejudo
• License: mit
• Created: 2016-02-13T00:15:10.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2016-02-15T13:14:07.000Z (almost 10 years ago)
• Last Synced: 2025-07-26T10:15:34.853Z (6 months ago)
• Language: JavaScript
• Homepage: https://www.npmjs.com/package/positional-notation
• Size: 14.6 KB
• Stars: 0
• Watchers: 0
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# positional-notation

[![Build Status](https://travis-ci.org/javiercejudo/positional-notation.svg)](https://travis-ci.org/javiercejudo/positional-notation)

[![Coverage Status](https://coveralls.io/repos/javiercejudo/positional-notation/badge.svg?branch=master)](https://coveralls.io/r/javiercejudo/positional-notation?branch=master)

[![Code Climate](https://codeclimate.com/github/javiercejudo/positional-notation/badges/gpa.svg)](https://codeclimate.com/github/javiercejudo/positional-notation)

Calculate the decimal equivalent given a base, a position and a decimal value

## Install

    npm i positional-notation

## Basic usage

```js

var fn = require('positional-notation');

fn(60, [1, 32]); //=> 1920

fn(5, [4, 3]); //=> 1875

```

## Arbitrary precision

```js

var Decimal = require('arbitrary-precision')(require('decimaljs-adapter'));

Decimal.setPrecision(50);

var d = require('to-decimal-arbitrary-precision')(Decimal);

fn.raw(d, 10, [2, 3/10]); // d(30)

```

 where `d` is a [`toDecimal`](https://github.com/javiercejudo/to-decimal) with at least `times` and `pow`.

## Use case: functional hex to dec

```js

const R = require('ramda');

const fn = require('positional-notation');

const symbols = {

  '0': '0', '1': '1', '2': '2', '3': '3', '4': '4', '5': '5', '6': '6', '7': '7', '8': '8', '9': '9',

  'A': '10', 'B': '11', 'C': '12', 'D': '13', 'E': '14', 'F': '15',

};

const posNotation = fn(Object.keys(symbols).length);

const hexToDec = R.pipe(

  R.toUpper,

  R.split(''),

  R.reverse,

  R.map(R.prop(R.__, symbols)),

  R.addIndex(R.map)(fn.mapper(posNotation)),

  R.sum

);

hexToDec('7E0'); //=> 2016

```

See [spec](test/spec.js).