Dynamic varname, avoid eval()

Question

I need to create a new instance of a class whose name is dynamically built by:

eval('SomeObject.'+id+' = new SomeClass'+Data.type+'(id, Data);');
// results in:
SomeObject._123 = new SomeClassWithDynamicName(id, Data);

it works fine, but i'd rather avoid the usage of eval (its almost impossible to track errors in code after an eval occured) and do something like this:

SomeObject[id] = new ('SomeClass'+Data.type)(id, Data);

score 2 · Accepted Answer · edited May 23 '17 at 12:06

2

Try this :

var SomeObject[id] = window['SomeClass'+Data.type];
SomeObject[id].setId(id);
SomeObject[id].setData(Data);

UPDATE : You can also try this if you don't have setters:

var SomeObject[id] = window['SomeClass'+Data.type](id, Data);

There is a similar question here : Instantiate a JavaScript Object Using a String to Define the Class Name

edited May 23 '17 at 12:06

Community

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answered May 04 '13 at 00:49

Akram Fares

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You're welcome, can you make the question as checked please ? – Akram Fares May 04 '13 at 01:32

score 1 · Answer 2 · answered May 04 '13 at 00:50

Do you really need to declare the classes globally as such? This would be a non-issue if you could register them on an object, like:

var classes = {};
classes.Type1 = function (id, data) { ... }
classes.Type2 = function (id, data) { ... }

var type = 'Type1';
var instance = new classes[type](id, data);

Dynamic varname, avoid eval()

2 Answers2