to print all combinations for states, given length

combo.js

function comb(len, states, rules){
	if(len>16){
		// return "out of limit, put force if you know better";
	}
	var states = states || ["0","1"];
	var pos = [];
	var powers = [];
	for (var i = 0; i < len; i++) {
		pos.push(0);
	};
	var rule = rules && rules[0];
	var ruleVal = 0;
	for (var i = 0; i < states.length; i++) {
		powers.push(Math.pow(len, i));
		if (!!rule) {
			ruleVal += rule[i]*powers[i];
		} else {
			ruleVal = rule;
		}
	};

	var shouldBreak, str;
	var output = [];
	do{
		shouldBreak = true;
		str = "";var s=0;
		for (var i = 0; i < len; i++) {
			str+= states[pos[i]];
			s+= powers[pos[i]];
		};
		// console.log('output',s, s==ruleVal, !ruleVal, str);
		// console.log('output', str);
		(!ruleVal || s==ruleVal) && output.push(str);
		for (var i = len-1; i >= 0; i--) {
			if(pos[i]<states.length-1){
				pos[i]++; break;
			}
			if(pos[i]<states.length){
				if (i==0) {
					shouldBreak = false; break;
				};
				pos[i]=0;
			}
		};
	}while(shouldBreak);
	return output;
}

// comb(2)
// comb(3)
console.time('s');
// var output = comb(6,['s','u','s','h','i','l'],[[1,1,1,1,1,1]]);
// var output = comb(6,['s','u','h','i','l']);
// var output = comb(3);
// var output = comb(6, ['l','n','o','r','u'],[[1,1,2,1,1]]);
var output = listCombName('meel');
console.log('output', JSON.stringify(output));
console.log('count = ', output.length);
console.timeEnd('s');


// console.time('s2');
// var output = comb(5,['a','a','a','b','c']);
// // console.log('output', output);
// console.log('count = ', output.length);
// console.timeEnd('s2');
//


// comb(18): 1241 ms, console inside
// comb(19): 2437 ms, console inside
// comb(20): 5220 ms, console inside
// comb(21): 13026 ms, console inside :count =  2097152
// comb(22): 23742 ms, console inside :count =  4194304
//// with --max_old_space_size=2000000
//// with --max_old_space_size=2000 :FATAL_ERROR
//// with --max_old_space_size=2500 :time = 32109 ms

function listCombName (s) {
	var sortedChars = [];
	sortedChars[0] = s[0];

	var rules = [];
	var freq = rules[0] = [];

	for (var i = 1,k=1; i < s.length; i++) {
		if(charInArray(s[i], sortedChars)) {continue;}
		sortedChars[k++] = s[i];
		for (var j = i; j > 0; j--) {
			if (sortedChars[j-1]>sortedChars[j]) {
				var t = sortedChars[j];
				sortedChars[j] = sortedChars[j-1];
				sortedChars[j-1] = t;
			};
		}
		// console.log(sortedChars);
	};
	for (var i = 0; i < sortedChars.length; i++) {
		freq[i] = freqInString(sortedChars[i], s);
	};
	function freqInString (c, s) {
		var r = 0;
		for (var i = 0; i < s.length; i++) {
			s[i] == c && r++;
		};
		return r;
	}
	function charInArray (c, arr) {
		for (var i = 0; i < arr.length; i++) {
			if(c==arr[i]){
				return true;
			}
		};
	}
	// console.log(sortedChars, rules);
	return comb(s.length, sortedChars, rules);
}
// listCombName('meenal')

has a bug:
test for (4,['a','b','c'],[[3,0,1]])

bug removed by major change #1