JSFiddle - React, Tailwind, and code Playground
JavaScript
function permutator(inputArr, amount, total) {
var results = [], out = [];
function permute(arr, memo) {
var cur, memo = memo || [];
var add = function (a, b) { return a + b; }
for (var i = 0; i < arr.length; i++) {
cur = arr.splice(i, 1);
if (arr.length === 0) {
results.push(memo.concat(cur));
}
var a = arr.slice();
var sum = memo.concat(cur).reduce(add);
if (memo.concat(cur).length === amount && sum === total) {
out.push(memo.concat(cur))
}
permute(a, memo.concat(cur));
arr.splice(i, 0, cur[0]);
}
return [results, out];
}
return permute(inputArr);
}
console.log(permutator([1,2,3,4], 3, 9))