type allergyProps = {
  filterAllergy: allergyArray[];
  setRemoveAllergy: Dispatch<SetStateAction<string>>;
  setSearchAllergy: Dispatch<SetStateAction<string>>;
};

type allergyArray = {
  id: number;
  name: string;
};

const Allergy = ({ setSearchAllergy, filterAllergy }: allergyProps) => {
  const [isInput, setIsInput] = useState(false);
  const [removeAllergy, setRemoveAllergy] = useState<string[]>([]);
  const handleInput = (e: React.ChangeEvent<HTMLInputElement>) => {
    if (e.target.value) {
      setIsInput(true);
    } else {
      setIsInput(false);
    }
    setSearchAllergy(e.target.value);
  };
  const click = (e: React.MouseEvent<HTMLButtonElement>) => {
    let value = e.currentTarget.name;
    setRemoveAllergy([...removeAllergy, value]);
    localStorage.setItem("allergy", removeAllergy); << #####error point !#######
  };

error name is Argument of type 'string[]' is not assignable to parameter of type 'string'.

   29 |     let value = e.currentTarget.name;
   30 |     setRemoveAllergy([...removeAllergy, value]);
 > 31 |     localStorage.setItem("allergy", removeAllergy);
      |                                     ^^^^^^^^^^^^^
   32 |   };

i want use to prevState for setItem,, how to use prevState of array type?

CodePudding user response：

localStorage cannot hold any data type except for strings. If you would still like to force it, you can convert the array into a string and then place it in localStorage as follows:

localStorage.setItem("allergy", JSON.stringify(removeAllergy));

When you want to read from localStorage, you would need to do this to get it back into the form of an array:

JSON.parse(localStorage.getItem("allergy"));