I have an "object of objects of arrays" and I simply need to get the total count of elements in the "bottom level" arrays ...so with the example below, I need to return 19 (counting elements a to s):
var arr={ 'AA': { 'aa': ['a','b'],
'bb': ['c','d'],
'cc': ['e','f'],
'dd': ['g','h'] },
'BB': { 'ee': ['i','j'],
'ff': ['k','l'] },
'CC': { 'gg': ['m','n'],
'hh': ['o','p'],
'ii': ['q','r','s'] } };
I have it working with this but it ain't pretty:
var cnt=0;
for(var f0 in arr){
for(var f1 in arr[f0]){
cnt+=arr[f0][f1].length;
}
}
It's probably best to use map and reduce but can't quite wrap my head around it. There are similar Q+A's (like this) but I couldn't quite find one that fits this situation.
Thanks!
By using Object.values to access the values associated with each key, you can use a nested reduce to count all the bottom level elements:
var arr={ 'AA': { 'aa': ['a','b'],
'bb': ['c','d'],
'cc': ['e','f'],
'dd': ['g','h'] },
'BB': { 'ee': ['i','j'],
'ff': ['k','l'] },
'CC': { 'gg': ['m','n'],
'hh': ['o','p'],
'ii': ['q','r','s'] } };
const cnt = Object.values(arr)
.reduce((c, o) => c + Object.values(o)
.reduce((c, a) => c + a.length,
0),
0);
console.log(cnt)