src/js/util/parse-utils.js
function detectDelimiter(input) {
	var numRows = input.split(/\r\n|\r|\n/).length;
	var numTabs = input.replace(tabRegex, "").length;

	if (numTabs >= numRows - 1) {
		return "\t";
	} else {
		return ",";
	}
}
function detectDelimiter(input) {
	var numRows = input.split(/\r\n|\r|\n/).length;
	var numTabs = input.replace(tabRegex, "").length;

	if (numTabs >= numRows - 1) {
		return "\t";
	} else {
		return ",";
	}
}
Detect delimiter of input algorithm: if numtabs >= numrows then TSV, else CSV