function toCamelCase(str, upperCaseFirst) {
    str = (str || '').toLowerCase().replace(/-(.)/g, function (match, group1) {
        return group1.toUpperCase();
    });

    if (upperCaseFirst && str) {
        str = str.charAt(0).toUpperCase() + str.slice(1);
    }

    return str;
}
Capital first
@param {string} str
@return {string}