Access array elements of dynamic arrayname

Question

I've got a lot of modules with checkboxes which I want to check, using an array. There are 3 packages with several modules. I generated a dropdown with the package names. After I choose a package, the checkboxes should get checked.

But I have a problem with the generated array name. I can't access it.

$("#package").change(function () {
    var starter = ["module1", "module2", "module3"];
    var advanced = ["module1", "module2", "module3", "module4", "module5"];
    var everything = ["module1", "module2", "module3", "module4", "module5", "module6", "module7"];    

    var contract = $('#package').val().toLowerCase();
    var arname = {};

    $.each(arname[contract], function( index, name ){
      $( "#module_" + name).prop('checked', true);  
    });     
});

How can I choose the array name, depending on the value of the dropdown #package?

so, contract will be either starter, advanced or everything? — Jaromanda X
– Jaromanda X, Commented Aug 7, 2016 at 8:51

Jaromanda X · Accepted Answer · 2016-08-07 08:54:00Z

1

rearrange your code slightly, like this

$("#package").change(function () {
    var arname = {
        starter: ["module1", "module2", "module3"],
        advanced: ["module1", "module2", "module3", "module4", "module5"],
        everything: ["module1", "module2", "module3", "module4", "module5", "module6", "module7"]
    }
    var contract = $('#package').val().toLowerCase();

    $.each(arname[contract], function( index, name ){
      $( "#module_" + name).prop('checked', true);  
    });     
});

which makes an object, arname, with properties starter, advanced, and everything

you can access those exactly like your original code

edited Aug 7, 2016 at 8:54

answered Aug 7, 2016 at 8:52

Jaromanda X

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5 Comments

T.J. Crowder Over a year ago

Or in ES2015+, using a Map.

T.J. Crowder Over a year ago

Please explain rather than just posting code. Before posting the answer, not later as an edit.

Jaromanda X Over a year ago

well, looking at the original code, I assumed he was so close he didn't need too much explanation

Jaromanda X Over a year ago

@T.J.Crowder - you should post an ES2015+ answer - I'd be interested in why map is a better alternative

T.J. Crowder Over a year ago

I'm not sure it is better in this case. The main advantages Map has over using an object are: 1. No potential conflict with inherited properties (but that can be mitigated using Object.create(null) to create the object), and 2. Keys can be things other than strings. In this case, there's no possibility of conflict, and the keys are strings, so... So Map is an alternative, but I'm not arguing that it's better.

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