I am trying to achieve something which seemed very basic but is getting me mad over the last days.
I have a simple array : ["a","b","c","d","e"] and I want to turn it into a nested JSON like this:
{"a":{"b":{"c":{"d":{"e":""}}}}}
Looping over it, I ran in problems like "how do you save the last key to set it afterwards without erasing it" and so on.
Does anyone has an idea?
You might have had problems because you were looping in the wrong direction. Try to build the object from inside-out:
array.reduceRight(function(v, key) {
var o = {};
o[key] = v;
return o;
}, "")
or, with a loop:
var val = "";
for (var i=array.length; i--; )
var o = {};
o[array[i]] = val;
val = o;
}
return val;
Here's one way to do it, recursively:
function convertToNestedObject(arr) {
var result = {};
if (arr.length === 1) {
result[arr[0]] = '';
} else {
result[arr[0]] = convertToNestedObject(arr.slice(1, arr.length));
}
return result;
}
You could pass the start index in to the function instead of using slice and creating copies of the array:
function convertToNestedObject(arr, startIndex) {
var result = {};
if (arr.length - startIndex === 1) {
result[arr[startIndex]] = '';
} else {
result[arr[startIndex]] = convertToNestedObject(arr, startIndex + 1);
}
return result;
}
Example: http://jsfiddle.net/jwcxfaeb/1/
arr.length == 0
arr.length is 0, then accessing the element at arr[0] will return undefined. Unless you meant changing the base case entirelyif (arr.length === 0) { return ''; } else { // recursive case }. Is that correct? If so, I don't see how it simplifies things that much. In any case, an iterative approach is much better for this problem anyway.Put current element as key and empty object ({}) as value. Continue with newly inserted empty object.
function toNested(arr){
var nested = {};
var temp = nested;
for(var i=0; i<arr.length; i++){
temp[arr[i]] = {};
temp = temp[arr[i]];
}
return nested;
}
