Javascript: build multidimensional Array programmatically

Question

My goal is to be able to keep track of my position/depth in a JSON tree by adding elements to an Array and then access nested nodes in the JSON utilizing this Array. By now say the Array foo it has one element:

foo = ["customers"]

so that element would act as a reference for a JSON children, say:

jsonTree["customers"]

where jsonTree is something like:

{ "customers":{ "name": "J. Goldsmith", "orders": [{ "order": "1", "order": "2" }] } }

Then foo eventually varies its size and become

foo = ["customers","orders"]

So the JSON reference would become

jsonTree["customers"]["orders"]

Now say that customers.orders can become customers.orders.order.date.etc.etc... Is there any way to build the jsonTree reference programmatically with N dimensions based on the N elements of foo Array?

Some examples:

I have ["John","Williams"] -> i want to build composer["John"]["Williams"] ["Erich","Wolfgang","Korngold"] -> i want to build composer["Erich"]["Wolfgang"]["Korngold"]

Would you also explain what you intend to do with this? It seems like a helper construct of some sort, what problem are you trying to solve? — Tomalak
– Tomalak, Commented Jul 10, 2013 at 15:43
Additionally, your sample object is not syntactically valid. Please set up a working sample on jsFiddle that demonstrates your problem. — Tomalak
– Tomalak, Commented Jul 10, 2013 at 15:46
@RocketHazmat An array of arrays has one dimension, that's the difference. Some of its members might be other one-dimensional arrays, but they don't have to be. It's a nested data structure. A multi-dimensional array is uniform. You can have an array of arrays that behaves like a multi-dimensional array, but that's neither the only way to build it nor is it enforced in any way. — Tomalak
– Tomalak, Commented Jul 10, 2013 at 15:52
@RocketHazmat, to be honest, I wasn't really sure either, but my friend Google revealed the following to me: stackoverflow.com/questions/597720/…. Although that question is specifically about C, the answers suffice for JS. — Derek Henderson
– Derek Henderson, Commented Jul 10, 2013 at 15:53
@Tomalak: So, a multi-dimensional array is an array of arrays where the dimensions are enforced? I never knew a structure like that existed! Guess that's what I get for coming from a PHP/JavaScript background. I've always used the term "multi-dimensional array" to describe a data-structure like: var multi = [[1,2,3],[4,5,6],[7,8,9]];. :-) I guess there's nothing stopping you from doing var multi = ['a',[1,2,3],'b',[4,5,6],'c',[7,8,9,10]]; :-P — gen_Eric
– gen_Eric, Commented Jul 10, 2013 at 15:56

Community · Accepted Answer · 2017-05-23 12:11:17Z

I think what you want is some sort of lookup function like that I describe here, except modified slightly to take an Array instead of multiple arguments

function generateLookupFunction(o) { return function lookup(arr) { var i, e = o; for (i = 0; i < arr.length; ++i) { if (!e.hasOwnProperty(arr[i])) throw "PathNotFoundError: " + arr.slice(0, i + 1).join('/'); e = e[arr[i]]; } return e; }; }

Then

var lookup = generateLookupFunction(jsonTree), foo = ["customers","orders"]; lookup(foo); /*[{ "order": "1", "order": "2" }] */

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