I am trying to dynamically create a chained JS object from an array, does anyone know how I can accomplish this?
UPDATE
I might have value.dog.cat = 'hello', and I'd like to access that variable.
/UPDATE
item = ['dog', 'cat']
How do I dynamically Create:
value['dog']['cat']
Any vanilla JS or jQuery would be cool.
I can't figure this out, because If I do a loop, eg:
new_value = {};
for (var i = 0; i < item.length(); i++) {
new_value += [item[i]; // This doesn't make sense
}
Just need to loop. Simple way is with reduce.
var details = {
dog : {
cat : "hello world"
}
};
var item = ['dog', 'cat'];
var value = item.reduce( function (prev, cur) {
return prev[cur]; //|| {}; Might want to include the commented out part if keys might not be defined
}, details);
console.log(value);Use Array.prototype.reduce to create the object or get the value
var itemArray = ['dog', 'cat'];
var itemObject = {};
itemArray.reduce(function(a, b) {
if (!a[b]) {
a[b] = {};
}
return a[b];
}, itemObject);
console.log(itemObject);
itemObject.dog.cat = 'test';
var value = itemArray.reduce(function(a, b) {
return a[b];
}, itemObject);
console.log(value);
If I have understood the question right then
var new_value = {};
for (var i = 1; i < item.length; i++)
{
new_value[item[i-1]] = item[i];
}
If value is an object, and value.dog is also an object with a property cat, you can indeed access value.dog.cat as value['dog']['cat']. Properties of objects can be accessed as string indexes, and you basically had it right. The only issue I saw in your question was the way in which you assigned properties to new_value in the first place.
value (JSON), not create new objects if that makes sense?
Just use Array.prototype.forEach()
The
forEach()method executes a provided function once per array element.
function setObject(o, p, v) {
p.forEach(function (a, i, aa) {
if (i === aa.length - 1) {
o[a] = v;
} else {
o[a] = o[a] || {};
o = o[a];
}
});
}
var item = ['dog', 'cat'],
value = {};
setObject(value, item, 'hello')
document.write(value.dog.cat);
document.write('<pre>' + JSON.stringify(value, 0, 4) + '</pre>');
valueis an existing object, which I'd like to turn intovalue['dog']['cat']for example, that way it will grab the right property fromvalue.