How to parse (infinite) nested object notation?
I am currently breaking my head about transforming this object hash:
"food": {
"healthy": {
"fruits": ['apples', 'bananas', 'oranges'],
"vegetables": ['salad', 'onions']
},
"unhealthy": {
"fastFood": ['burgers', 'chicken', 'pizza']
}
}
to something like this:
food:healthy:fruits:apples
food:healthy:fruits:bananas
food:healthy:fruits:oranges
food:healthy:vegetables:salad
food:healthy:vegetables:onions
food:unhealthy:fastFood:burgers
food:unhealthy:fastFood:chicken
food:unhealthy:fastFood:pizza
In theory it actually is just looping through the object while keeping track of the path and the end result.
Unfortunately I do not know how I could loop down till I have done all nested.
var path;
var pointer;
function loop(obj) {
for (var propertyName in obj) {
path = propertyName;
pointer = obj[propertyName];
if (pointer typeof === 'object') {
loop(pointer);
} else {
break;
}
}
};
function parse(object) {
var collection = [];
};
There are two issues which play each out:
- If I use recurse programming it looses the state of the properties which are already parsed.
- If I do not use it I cannot parse infinite.
Is there some idea how to handle this?
Regards
Answers:
The reason your recursive function doesn't work is you're storing the state outside it. You want the state inside it, so that each invocation tracks its state.
Something like this:
var obj = /* ... the object ... */;
var lines = loop([], "", obj);
function loop(lines, prefix, obj) {
var key, sawOne = false;
// Is it an array?
if (Object.prototype.toString.call(obj) === "[object Array]") {
// Yes, in your example these are all just strings to put
// at the end, so do that
for (key = 0; key < obj.length; ++key) {
lines.push(prefix + ":" + obj[key]);
}
}
else {
// No, it's an object. Recurse for each property, adding the
// property to the prefix we use on each line
for (key in obj) {
loop(lines, prefix ? (prefix + ":" + key) : key, obj[key]);
}
}
return lines;
}
Completely off-the-cuff and untested, but you get the idea.
Edit: But apparently it works, as Michael Jasper was kind enough to make a live demo (source) which I've tweaked slightly.