Longest Common Substring & longest consecutive substring javascript implementation.

longestConsecutiveSubstr-longestCommonSubstring.js

function longestConsecutiveSubstr(str) {
	var longestConsecutiveSubstr = '';
	var leftOff = 1;

	for (var a = 0; a < str.length - 1; a = leftOff) {
		var newLongestConsecutiveSubstr = '';

		for (var b = a + 1; b < str.length; b++) {
			if (str[a] == str[b]) {
				newLongestConsecutiveSubstr += str[a];
				if (b == a + 1) {
					newLongestConsecutiveSubstr += str[a];
				}
			} else {
				break;
			}
		}

		if (newLongestConsecutiveSubstr.length > longestConsecutiveSubstr.length) {
			longestConsecutiveSubstr = newLongestConsecutiveSubstr;
		}

		leftOff = b;
	}

	return longestConsecutiveSubstr;
}

function longestCommonSubstring() {
	var longestConsecutiveSubstrs = [];
	var assertions = [];

	for (var a = 0; a < arguments.length; a++) {
		longestConsecutiveSubstrs.push(longestConsecutiveSubstr(arguments[a]));
	}

	for (a = 0; a < arguments.length; a++) {
		for (var b = a + 1; b < arguments.length; b++) {
			if (longestConsecutiveSubstrs[a] == longestConsecutiveSubstrs[b]) {
				assertions.push({
					strings: [arguments[a], arguments[b]],
					common: longestConsecutiveSubstrs[a]
				});
			} else {
				assertions.push({
					strings: [arguments[a], arguments[b]],
					common: null
				});
			}
		}
	}

	return assertions;
}

console.log(longestCommonSubstring('airproof', 'door', 'room'));

console.log('tesssssssst', longestConsecutiveSubstr('tesssssssst'));
console.log('tessssssssttttttttttttt', longestConsecutiveSubstr('tessssssssttttttttttttt'));
console.log('teeeeeeeeeeeeeeesssssssstttttt', longestConsecutiveSubstr('teeeeeeeeeeeeeeesssssssstttttt'));
// console.log(longestConsecutiveSubstr('airproof'));
// console.log(longestConsecutiveSubstr('door'));
// console.log(longestConsecutiveSubstr('room'));