gulp-responsive-modern/lib/size.js

gulp responsive images

'use strict'

const _ = require('lodash')

module.exports = function size (neededSize, originalSize) {
  if (neededSize === undefined || neededSize === null) {
    return null
  } else if (_.isString(neededSize) && neededSize.indexOf('%') > -1) {
    const percentage = parseFloat(neededSize)
    if (isNaN(percentage)) {
      throw new Error('Wrong percentage size "' + neededSize + '"')
    }
    return Math.round(originalSize * percentage * 0.01)
  } else {
    neededSize = parseInt(neededSize)
    if (isNaN(neededSize)) {
      throw new Error('Wrong size "' + neededSize + '"')
    }
    return neededSize
  }
}