var obj = {
"1": [111, 222],
"2": [333],
"3": [444, 555]};
var arr = [];
for (var i in obj) {
arr.push(...obj[i]);}
console.log (arr);
or
var obj = {
"1": [111, 222],
"2": [333],
"3": [444, 555]};
var arr = [];
for (var i in obj) {
for(var j in obj[i]){
arr.push(obj[i][j]);
} }
console.log (arr);
or
var arr = [];
for (var i in obj) {
arr=arr.concat(obj[i]);}
console.log (arr);
it would be easy to make reasonable use of the ES2015 feature.
var obj = {
"1": [111, 222],
"2": [333],
"3": [444, 555]};
let arr = Object.values (obj). Reduce ((afort b) = > a.concat (b)); / / [111222333444555]