'use strict';

/**
 * Internal conversion helper
 */
module.exports = function strToCamelCase(str) {
  if (typeof str !== 'string') {
    throw new Error('String expected for conversion to snake case');
  }
  return str
    .trim()
    .replace(/_+|\-+/g, ' ')
    .replace(/(?:^\w|[A-Z]|\b\w|\s+)/g, function(match, index) {
      if (Number(match) === 0) {
        return '';
      }
      return (index === 0) ? match.toLowerCase() : match.toUpperCase();
    });
};