[
["1","2","3"],
["4","5","6"],
["7","8","9"]
];
var new arr =[]；
設I = 0；
oldarr[0]。forEach(e1= >{
oldarr[1]。forEach(E2 = & gt；{
oldarr[2]。forEach(E3 = & gt；{
new arr[i++]= e 1+E2+E3；
})
});
console . log(JSON . stringify(new arr))；