function permutation(array){
    return array.reduce(function(prev,current){
        var res = [];
        prev.forEach(function(pe){
            if(!pe['length']) pe = [pe];
            return current.forEach(function(ce){
                res.push(pe.concat([ce]))
            })
        })
        return res
    })
}
 
function combination(array){
    return array.reduce(function(prev,current){
        var res = [];
        prev.forEach(function(pe){
            if(!pe['length']) pe = [pe];
            return current.forEach(function(ce){
                var r = pe.concat([ce])
                r.sort()
                if(!res.some(function(f){
                    return f.every(function(ff, i){
                        return ff == r[i]
                    })
                })){
                    res.push(r)
                }
            })
        })
        return res
    })
}
var a = [1,2]
var b = [2,1]
var c = [2,1]
var d = [a,b,c]
console.log('----- all combinations')
combination(d).forEach(function(e){
  console.log(e)
})
console.log('----- all permutations')
permutation(d).forEach(function(e){
  console.log(e)
})
 
// ----- all combinations
// [1, 2, 2]
// [1, 1, 2]
// [1, 1, 1]
// [2, 2, 2]
// ----- all permutations
// [1, 2, 2]
// [1, 2, 1]
// [1, 1, 2]
// [1, 1, 1]
// [2, 2, 2]
// [2, 2, 1]
// [2, 1, 2]
// [2, 1, 1]