I have an array with nested objects, such as this one:
[
{"name": "1", "children": [{"name": "1.1", "children":"1.2"}]},
{"id": "2", "thing": [{"name": "2.1", "children":"2.2"}]},
{"name": "3", "stuff": [{"name": "3.1", "children":"3.2"}]},
]
The objects can contain values of different types, including other, nested objects.
I want to convert this array to CSV format.
I've tried to iterate with for .. in
loops, regular nested for
loops, .map()
and recursion. I think recursion might be the only way to solve this particular problem, though. For the CSV field names I want to use the sequence of keys that lead to the value.
For the given example, the CSV result I'm looking for is:
name, children.name, children.children,id, thing.name, thing.children, stuff.name, stuff.children
1, 1.1, 1.2,
,,,2,2.1,2.2
3,,,,3,3.1,3.2
You could use this ES6 function to create the 2D array you are looking for, which you can then easily transform to CSV:
function pivot(arr) {
var mp = new Map();
function setValue(a, path, val) {
if (Object(val) !== val) { // primitive value
var pathStr = path.join('.');
var i = (mp.has(pathStr) ? mp : mp.set(pathStr, mp.size)).get(pathStr);
a[i] = val;
} else {
for (var key in val) {
setValue(a, key == '0' ? path : path.concat(key), val[key]);
}
}
return a;
}
var result = arr.map( obj => setValue([], [], obj) );
return [[...mp.keys()], ...result];
}
function toCsv(arr) {
return arr.map( row =>
row.map ( val => isNaN(val) ? JSON.stringify(val) : +val ).join(',')
).join('\n');
}
// Sample data
var arr = [
{"name": "1", "children": [{"name": "1.1", "children":"1.2"}]},
{"id": "2", "thing": [{"name": "2.1", "children":"2.2"}]},
{"name": "3", "stuff": [{"name": "3.1", "children":"3.2"}]},
];
// Conversion to 2D array and then to CSV:
console.log(toCsv(pivot(arr)));
.as-console-wrapper { max-height: 100% !important; top: 0; }
For other ways to convert a 2D array to CSV, see this Q&A.
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