Function _format

src/utils/string.js:63–112

(value, options)

}

function _format (value, options) {
  if (typeof value === 'number') {
    return formatNumber(value, options)
  }

  if (isBigNumber(value)) {
    return formatBigNumber(value, options)
  }

  // note: we use unsafe duck-typing here to check for Fractions, this is
  // ok here since we're only invoking toString or concatenating its values
  if (looksLikeFraction(value)) {
    if (!options || options.fraction !== 'decimal') {
      // output as ratio, like '1/3'
      return `${value.s * value.n}/${value.d}`
    } else {
      // output as decimal, like '0.(3)'
      return value.toString()
    }
  }

  if (Array.isArray(value)) {
    return formatArray(value, options)
  }

  if (isString(value)) {
    return stringify(value)
  }

  if (typeof value === 'function') {
    return value.syntax ? String(value.syntax) : 'function'
  }

  if (value && typeof value === 'object') {
    if (typeof value.format === 'function') {
      return value.format(options)
    } else if (value && value.toString(options) !== {}.toString()) {
      // this object has a non-native toString method, use that one
      return value.toString(options)
    } else {
      const entries = Object.keys(value).map(key => {
        return stringify(key) + ': ' + format(value[key], options)
      })

      return '{' + entries.join(', ') + '}'
    }
  }

  return String(value)
}

/**
 * Stringify a value into a string enclosed in double quotes.