json - JavaScript Closures, Really simple example with jsFiddle -

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i'm pulling hair out trying understand javascript closures. i'm looking closely @ this example. actual code in node.js don't think that's major issue (except error codes..)

here's slimmed down code:

var jsonsymbols = {      "id5": "wfc",      "id4": "amzn",      "id3": "baba",      "id2": "yhoo",      "id1": "goog",      "id0": "aapl"  };  // assume unknown number of stock symbols..     var count = 0;  var outputprices = {};  (key in jsonsymbols) {      outputprices['newid' + count]['price'] = get_price(jsonsymbols[key], count, function() {          console.log("  dummy function"); // callback function used when looking 1 stock.      });      count++;  }  console.log("\ncount = " + count);  console.log("\noutput = " + json.stringify(outputprices));    function get_price(symbol, countindex, callback) {      setinterval(function() {          // nothing... actual function makes http call server           // , stock price lookup.  can 1 stock @ time,           // hence repeated calls.      }, 1000);      return 124.12;      callback();  };

(hmmm. i'm new snippet stuff. i've created jsfiddle ) current error code uncaught typeerror: cannot set property 'price' of undefined i'm missing stupid. there way have cake , drink beer too? i'm learning how asynchronous stuff works, unfortunately have difficult time beginning learning process in pure abstract concepts. need concrete example start, , can extrapolate abstract.

anybody been here before? why doesn't work? thx.


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