number-name/src/Converter.ts

import NumberSystem from './NumberSystem'
import ConverterStream from './ConverterStream'
import { ReadStreamOptions, ConvertOptions } from './common'

export default class Converter {
  constructor(private readonly system: NumberSystem) {}

  convert(value: string | number | bigint, options: ConvertOptions) {
    let converted: string[] = []
    switch (typeof value!) {
      case 'string':
        return ''
      case 'bigint':
      case 'number':
        let current = value as number
        let thousandPower = 0
        while (current > 0) {
          const hundreds = Math.floor((current % 1000) / 100)
          const tens = Math.floor((current % 100) / 10)
          const ones = Math.floor(current % 10)
          if (!(ones === 0 && tens === 0 && hundreds === 0)) {
            if (thousandPower > 0) {
              const { scale = 'short' } = options
              converted.unshift(this.system.getKiloName[scale!]!(thousandPower))
            }
            converted.unshift(this.system.getKiloCount(hundreds, tens, ones))
          }

          thousandPower = thousandPower + 1
          current = Math.floor(current / 1000)
        }
        return converted.join(' ')
      default:
        break
    }
    throw TypeError('Invalid argument passed to value.')
  }

  readStream(options: ReadStreamOptions): ConverterStream {
    const { scale = 'short', encoding = 'utf-8' } = options
    return new ConverterStream(this.system, { scale, encoding })
  }
}