В ES2017 вы можете сделать:
Object.entries(obj).map(([name, size])=> ({name, size}))
var obj = {
"Central":73322346.47533998,
"East":87801368.39711998,
"North":76468694.37534,
"South":142687496.66816995,
"West":76815749.40554999
}
var res = Object.entries(obj).map(([name, size])=> ({name, size}));
console.log(res);
В ES2011 (5.1), ES2015 (6), .... и далее вы можете сделать:
Object.keys(obj).map(function(k) {
return {name: k, size: obj[k]}
})
var obj = {
"Central":73322346.47533998,
"East":87801368.39711998,
"North":76468694.37534,
"South":142687496.66816995,
"West":76815749.40554999
}
var res = Object.keys(obj).map(function(k) {
return {name: k, size: obj[k]}
})
console.log(res)