Calling a variable to reference an array

Question

I am trying to call a string variable to reference an array variable.

message1[0][0] = "Hello."; // existing array
var caller = ['message1', 'message2', 'message3'];

alert(message1[0][0]);

But instead of using the message1 array in the alert, I want to use caller[0] (which is equal to "message1") so that it displays "Hello". How do you do this? This doesn't seem to work:

alert(caller[0][0][0]);

Answer 1

The best way is to put message1 on an object, then use [] notation to index into the object:

 var obj = { message1: [ ["Hello.", "two", "three"] ] }; var caller = ['message1', 'message2', 'message3']; alert(obj[caller[0]][0][0]); 

If message1 is a global variable, it's already on an object — the global object, which you can access as window on browsers. So if it's a global, you could use:

alert(window[caller[0]][0][0]);

But global variables are a Bad Idea ^(tm) , so best to use your own object instead.

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Full disclosure: You can also use eval to do it, but it's a big hammer for a task this small. Just for completeness:

alert(eval(caller[0] + "[0][0]"));

I don't recommend it, but provided you're fully in control of the text you pass into it, it's workable. Much better to use an object, though.