Using .Filter When the Filter Criteria are in Pre-existing String (TypeScript/Node.js) - arrays

Question

I'm trying to process an array of JSON objects that have various common attributes, filtering each array entry on one or more of those attributes.
Normally, I'd just do it something like this:
let filteredResultsArray = originalArray.filter((obj) => {
return obj.attribute1 <= 3 && obj.attribute2 > 0 && obj.attribute3 === 10;
});
My problem is that the filter parameters (the part after "return" in the code above) are highly variable (and unpredictable) from run to run, so I can't hard-code them in the filter. I compute them on the fly and store the whole thing in a string in my code. For example, on one run it might be:
myAttributeString = "obj.attribute1 <= 3 && obj.attribute2 > 0 && obj.attribute3 === 10";
I've tried doing this:
let filteredResultsArray = originalArray.filter((obj) => {
return myAttributeString;
});
That's failing to filter anything. Apparently .filter() is not properly interpreting what I've stored in myAttributeString as filter criteria.
I have a sneaking suspicion that eval(myAttributeString) might be one way to pull this off, but unfortunately I'm working on a team where we've got tslint set to disallow the use of eval(), so that's not an option.
Anybody have an idea how I can get this to work?

Answer 1

When you "compute them on the fly", instead of creating a string, create a callback function that you can then pass to filter. For example, instead of
const myAttributeString = "obj.attribute1 <= 3 && obj.attribute2 > 0 && obj.attribute3 === 10";
do
const filterCallback = obj => obj.attribute1 <= 3 && obj.attribute2 > 0 && obj.attribute3 === 10
Then, later, when the appropriate time comes to .filter, simply pass that as the callback:
const filteredResultsArray = originalArray.filter(filterCallback);
If you can't pass functions around, another option would be to build an array of conditions, for example
[
{
prop: "attribute1",
constraint: "<=",
value: 3
},
{
prop: "attribute2",
constraint: ">",
value: 0
},
// ...
]
and then turn the object into the filter function needed.

Answer 2

****************************************UPDATE******************************
As I suspected, eval() did work, but since I can't use it in my delivered code, and thanks to CertainPerformance's suggestion (which put my thinking on the right track) as well as the Node.js documentation site (via a lucky Google search), I was able to find a workaround using the vm module:
import * as vm from "vm";
let filteredResultsArray = originalArray.filter(
vm.runInThisContext("(obj) => {
return " + myAttributeString + ";}"));
Case closed.