dynamically creating an associative array

Question

dynamically creating an associative array

I'm looking to take a hash, create a deep series of keys and then append another hash to the end.

given...

var hash_a = {'foo': 'bar'}
var hash_b = {'alpha': 'beta'}
var array = ['a', 'b', 'c']

how can I generate the following?

{
  'foo': 'bar',
  'a':{
    'b':{
      'c': {
        'alpha': 'beta'
       }
    }
  }
};

javascript
node.js
associative-array

Answer 1

This should do the trick:

var hash_a = {'foo': 'bar'};
var hash_b = {'alha': 'beta'};
var array = ['a', 'b', 'c'];

function build(a,b,c){
    var o=c.reduceRight(function(o, n){ var b={}; b[n]=o; return b; }, b);
    for(x in a){ o[x]=a[x]; }
    return o;
}

Here is the fiddle to play with. See MDN for further explanation of Array.prototype.reduceRight().