text: 'use strict';
  
  const getRadixFromKey = require('./getRadixFromKey'),
        head            = require('./head'),
        last            = require('./last');
  
  module.exports = pair => {
    const baseFrom = getRadixFromKey(head(pair)),
          baseTo   = getRadixFromKey(last(pair)),
          method   = head(pair) + '2' + last(pair);
  
    return {
      [method] : (s) => parseInt(s, baseFrom).toString(baseTo)
    };
  };
  