javascript .includes method not working as expected

Question

I am working with the stripe API to get a list of all used products in my subscriptions. I am going through all subscriptions and adding the used products into an array (or I'm trying to).

I only want to add a product if it has not been added in yet.

router.get('/getusedproducts', asyncHandler(async(req,res,next) => {
  var products = [];
  for await (const subscription of stripe.subscriptions.list()) {
    for (i = 0; i < subscription.items.data.length; i++) {
      var prod = subscription.items.data[i].plan.product;
      if (!products.includes[prod]){
        products.push(prod)
        console.log(prod);
      }
    }
  }
  res.send(products)
}));

Currently, this piece of code isn't working as intended because I am still seeing the console log all product. Ideally, the check !products.includes[prod] should prevent that, but it isn't. I've read several discussion here on stack (1)(2)(3)

Not sure exactly how to compare the items in the array to the new ones I'm getting from JSON object to check if exists.

Any help is appreciated.

`!products.includes(prod)` not `!products.includes[prod]`, `.includes` is function — ponury-kostek, Nov 30 '18 at 13:39
Why would that not throw an error? Is that just a JS quirk? I'd expect that to just not work if I used incorrect syntax there... @ponury-kostek — mufc, Nov 30 '18 at 13:47
Because `.includes` exists and you can access it's properties with `[prod]` — ponury-kostek, Nov 30 '18 at 13:48

score 0 · Answer 1 · answered Nov 30 '18 at 14:00

includes is method so has to be used like somArray.includes(value).

Please be aware that includes method is not supported in IE or Edge<14. If you are not targeting IE/Edge<14 then no issues there. Otherwise, use the good old indexOf method to look for elements in array.

javascript .includes method not working as expected

1 Answers1