Javascript Add Array Element to Dynamically Named Index

Question

Given

var input[[]];

$('some_selector').each(function() {
   var outer, inner; 
   outer=$(this).parent().attr('some_property');
   inner=$(this).attr('a_property');
   input[outer].push(inner);
});

An error is encountered during the push function. Is it because the specific input[outer] is not declared as array?

Also, the value of outer is not necessarily sorted. So within the loop, outer can sequentially have values of: "property1","property2","property1","property3","property2" ...

In PHP terms, is there something equivalent to:

foreach () {
    $input[$outer][]=$inner;
}

Thanks!

Answer 1

If outer has values like "property1", etc., then input isn't an array. It's an object. Unlike PHP, there are no associative arrays in Javascript.

Try:

var input = {};

And yes, you'll need to create an array before pushing to it. You can do that in one "maybe it exists, maybe it doesn't" step like so:

input[outer] = input[outer] || [];

and then push as before:

input[outer].push(inner);