string calculator kata

stringCalc.js

var assert = require('chai').assert;

function findDelimiter (numbers) {
	var parseDelim = numbers.match(/\/\/(.*),/);
	if (!parseDelim) {
		return ",";
	}
	return parseDelim[1];
}

function normalizeDelimiter (numbers) {
	numbers = numbers.replace('\n', ',');
	var delim = findDelimiter(numbers);
	
	return numbers
		.replace('//' + delim + ",", "")
		.replace(delim, ',');
}

function detectNegatives (numbers) {
	return numbers.filter(function(x) {
		return x < 0;
	});
}

var add = function(numbers){
	var parseNums = function(x) { return parseInt(x) || 0; }
	var sum = function(sum, current) { return sum + current; };

	var parsed = normalizeDelimiter(numbers)
		.split(',')
		.map(parseNums);

	var negatives = detectNegatives(parsed);
	if (negatives.length) {
		throw new Error("Negative numbers: " + negatives.join(','));
	}

	return parsed.reduce(sum, 0);
};

console.log("Running tests", new Date() );
  
assert.equal(add(""), 0, "empty string");
assert.equal(add("1"), 1, "one");
assert.equal(add("1,2"), 3, "2 numbers");
assert.equal(add("1,2,3,4"), 10, "multiple numbers");
assert.equal(add("1,2,3\n4"), 10, "newline");
assert.equal(add("//;\n1;2"), 3, "custom delimiter");
assert.equal(add("//asd\n1asd2"), 3, "custom delimiter");

assert.throws(function() { add("-1"); },
	Error,
	"Negative numbers: -1",
	"Detect 1 negative");

assert.throws(function() { add("-1,-2"); },
	Error,
	"Negative numbers: -1,-2",
	"Detect 2 negatives");


console.log('Done');