With using only one reduce() you can do this. you don’t need map().
better approach is this:
const values = [1,2,3,4];
const newValues= values.reduce((acc, cur) => {
return acc.concat([cur*cur , cur*cur*cur, cur+1]);
// or acc.push([cur*cur , cur*cur*cur, cur+1]); return acc;
}, []);
console.log('newValues=", newValues)EDIT:
The better approach is just using a flatMap (as @ori-drori mentioned):
const values = [1,2,3,4];
const newValues = values.flatMap((v) => [v *v, v*v*v, v+1]);
console.log(JSON.stringify(newValues)); //[1, 1, 2, 4, 8, 3, 9, 27, 4, 16, 64, 5]