code: function camelCase(str, next) {
      let output = '';
      for (const c of str) {
          if (c === '_') {
              next = true;
              continue;
          }
          output += next ? c.toUpperCase() : c;
          next = false;
      }
      return output;
  }
docs: Converts foo_bar -> fooBar
  @param str
  @param next
  @returns {string}