SOURCE

function findCombinations(n){
    const result = [];
    function backtrack(target,start,path){
        if(target === 0){
            result.push([...path])
            return
        }
        for(let i=start;i<=n;i++){
            if(i>target) break;
            path.push(i);
            backtrack(target-i,i,path);
            path.pop()
        }
        
    }
    backtrack(n,1,[]);
    return result
}
console.log(findCombinations(4))