Question

This code works, in some cases. If it returns console.log then the call to p.out functions just fine.

function Notice(mode) {
    this.debug = mode;

    this.out = (function() {
            if(mode) {
                if(window.console) {
                    return console.log;
                } else {

                    return alert;
                }
            } else {
                return Notice.doNothing;
            }
    })(mode);
}

var p = new Notice('1');
p.out('Kool-aid, OH YEAH!');

However, when it returns alert (or window.alert) I get an error:

Error: uncaught exception: [Exception... "Illegal operation on WrappedNative prototype object"  nsresult: "0x8057000c (NS_ERROR_XPC_BAD_OP_ON_WN_PROTO)"  location: "JS frame :: http:// .. :: <TOP_LEVEL> :: line 22"  data: no]

And as a simple test, this works:

out = (function() { return alert; })();
out('hello dolly');

How can I get obj.out to function properly when its being set to alert?

Answer 1

Why not return an anonymous function that in return calls the build-in function?

Something like

return function(msg) { alert(msg); }