[FIXED] How to give type for new Set typescript?

Issue

I have new Set and want to put it in props or in argument of function.

 const [selectedIds, setSelectedIds] = React.useState(new Set([]));

How can i write types for that?

For example, I have a function, that will in arguments get new Set

const onSelect = (selectedIds // here i want to write type, it is argument from newSet) => {
    const newSelectedIds = new Set(selectedIds);

    if ( selectedIds.has(selectedId) ) {
      newSelectedIds.delete(selectedId);
    } else {
      newSelectedIds.add(selectedId);
    }
    setSelectedIds(newSelectedIds);
  };

Solution

The Set class is generic. You can pass the type of the elements like this:

const [selectedIds, setSelectedIds] = React.useState(new Set<string>([]))

Since it's a class, it can also be used as a type:

const onSelect = (selectedIds: Set<string>) => {...}

Answered By - nullptr
Answer Checked By - - David Goodson (ReactFix Volunteer)