'Getting errors while trying some condition on an array

Trying to check if an array has some values and display it once in typescript

const items = products?.reduce((prev: any, current) => {
  if (!current?.data()?.drinkName in prev) {
    prev[current?.data()?.category] = [];
  }
   prev[current?.data()?.category].push(current?.data()?.category);
   return prev;
}, {});

Error:

The left-hand side of an 'in' expression must be a private identifier or of type 'any', 'string', 'number', or 'symbol'.

typescript

Solution 1:^[1]

You accidentally converted current?.data()?.drinkName to a boolean by adding ! before it. Try wrapping the whole statement with parenthesis like so !(current?.data()?.drinkName in prev). This way the ! negates the whole statement and not just the left part.

I would have also added a condition that checks whether current?.data()?.drinkName is null before checking if it exists in prev, because theoretically prev might contain null.

if (!(current?.data()?.drinkName) || !(current?.data()?.drinkName in prev))

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Solution 1	Niv Kor

'Getting errors while trying some condition on an array

Solution 1:[1]

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Solution 1:^[1]