compromise/src/result/subset/values/toText/index.js

natural language processing in the browser

'use strict';
// turns an integer/float into a textual number, like 'fifty-five'

//turn number into an array of magnitudes, like [[5, million], [2, hundred]]
const breakdown_magnitudes = function(num) {
  let working = num;
  let have = [];
  const sequence = [
    [1000000000, 'million'],
    [100000000, 'hundred million'],
    [1000000, 'million'],
    [100000, 'hundred thousand'],
    [1000, 'thousand'],
    [100, 'hundred'],
    [1, 'one']
  ];
  sequence.forEach((a) => {
    if (num > a[0]) {
      let howmany = Math.floor(working / a[0]);
      working -= howmany * a[0];
      if (howmany) {
        have.push({
          unit: a[1],
          count: howmany
        });
      }
    }
  });
  return have;
};

//turn numbers from 100-0 into their text
const breakdown_hundred = function(num) {
  const tens_mapping = [
    ['ninety', 90],
    ['eighty', 80],
    ['seventy', 70],
    ['sixty', 60],
    ['fifty', 50],
    ['forty', 40],
    ['thirty', 30],
    ['twenty', 20]
  ];
  const ones_mapping = [
    '',
    'one',
    'two',
    'three',
    'four',
    'five',
    'six',
    'seven',
    'eight',
    'nine',
    'ten',
    'eleven',
    'twelve',
    'thirteen',
    'fourteen',
    'fifteen',
    'sixteen',
    'seventeen',
    'eighteen',
    'nineteen'
  ];
  let arr = []
  for (let i = 0; i < tens_mapping.length; i++) {
    if (num >= tens_mapping[i][1]) {
      num -= tens_mapping[i][1];
      arr.push(tens_mapping[i][0])
    }
  }
  //(hopefully) we should only have 20-0 now
  if (ones_mapping[num]) {
    arr.push(ones_mapping[num])
  }
  return arr
};

/** print-out 'point eight nine'*/
const handle_decimal = (num) => {
  const names = [
    'zero',
    'one',
    'two',
    'three',
    'four',
    'five',
    'six',
    'seven',
    'eight',
    'nine'
  ]
  let arr = []
  //parse it out like a string, because js math is such shit
  let decimal = ('' + num).match(/\.([0-9]+)/)
  if (!decimal || !decimal[0]) {
    return arr
  }
  arr.push('point')
  let decimals = decimal[0].split('')
  for (let i = 0; i < decimals.length; i++) {
    arr.push(names[decimals[i]])
  }
  return arr
}

/** turns an integer into a textual number */
const to_text = function(num) {
  let arr = []
  //handle negative numbers
  if (num < 0) {
    arr.push('negative')
    num = Math.abs(num);
  }
  //break-down into units, counts
  let units = breakdown_magnitudes(num);
  //build-up the string from its components
  for (let i = 0; i < units.length; i++) {
    let unit_name = units[i].unit;
    if (unit_name === 'one') {
      unit_name = '';
      //put an 'and' in here
      if (arr.length > 1) {
        arr.push('and')
      }
    }
    arr = arr.concat(breakdown_hundred(units[i].count))
    arr.push(unit_name)
  }
  //also support decimals - 'point eight'
  arr = arr.concat(handle_decimal(num))
  //remove empties
  arr = arr.filter((s) => s)
  if (arr.length === 0) {
    arr[0] = 'zero'
  }
  return arr
};

module.exports = to_text;

// console.log(to_text(-1000.8));