Alternative to eval

Question

I am making some common function where in I pass the array, name of field from array, value of field in array and return field name to return value as below

function arrayFilter(_array, findField, value, returnField) {
 var temp = "_array[i]." + findField;
 var retValue = "";
 for (var i = 0; i < _array.length; i++) {
   if (eval(temp) == value) {
  return eval("_array[i]." + returnField);
  }
 }
}

But when I read on Internet I found that eval is not good, it can have string injection attack.

So somebody help on above.

Have you got an example of the type of array you're looping over? — Andy, Feb 24 '14 at 11:42
I ask only because there have got to be far better ways of doing what you want to do if you restructure your array better. — Andy, Feb 24 '14 at 11:44
I don't really understand why even people ask that. How do they learn about `eval` before extremely basics that is `[]`? — Oleg V. Volkov, Feb 24 '14 at 11:46

score 3 · Accepted Answer · answered Feb 24 '14 at 11:38

3

Instead of:

return eval("_array[i]." + returnField);

Try:

return _array[i][returnField];

And also read this article.

answered Feb 24 '14 at 11:38

Danilo Valente

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techfoobar · Answer 2 · 2014-02-24T11:54:19.993

1

You can use the square bracket notation for accessing properties when the value of your key is unknown.

function arrayFilter(_array, findField, value, returnField) {
 var temp = _array[i][findField];
 var retValue = "";
 for (var i = 0; i < _array.length; i++) {
   if (temp == value) {
     return _array[i][returnField];
   }
 }
}

edited Feb 24 '14 at 11:54

answered Feb 24 '14 at 11:41

techfoobar

65,616
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Alternative to eval

2 Answers2