indent = (str, prefix, noPrefixInFirstLine) => {
	const rem = str.replace(/\n([^\n])/g, `\n${prefix}$1`);
	if (noPrefixInFirstLine) return rem;
	const ind = str[0] === "\n" ? "" : prefix;
	return ind + rem;
}
@param {string} str a string
@param {string} prefix prefix
@param {boolean=} noPrefixInFirstLine need prefix in the first line?
@returns {string} result