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Object Literal instead of switch

I would like to use object literal instead of switch statement, but i got this error:

Element implicitly has an ‘any’ type because expression of type ‘string’ can’t be used to index type ‘{ apple: string[]; orange: string[]; watermelon: string[]; default: void; }’. No index signature with a parameter of type ‘string’ was found on type ‘{ apple: string[]; orange: string[]; watermelon: string[]; default: void;}’ ts(7053)*

SWITCH STATEMENT

const fruits = (fruit: string): string[] => {
    switch (fruit) {
      case 'apple': {
        return state.apple;
      }
      case 'orange': {
        return state.orange;
      }
      case 'watermelon': {
        return state.watermelon;
      }
      default: {
        return ('Not found');
      }
    }
  };

OBJECT LITERAL

const fruits = (fruit: string): string[] => {
   const fruitCategory = {
     apple: state.apple,
     orange: state.orange,
     watermelon: state.watermelon,
     default: 'Not Found',
  };
  return fruitCategory[fruit] ?? fruitCategory.default;

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Answer

You could give your fruitCategory object an index signature to indicate that it can be indexed by any string value.

const fruits = (fruit: string): string[] => {
  const fruitCategory: Record<string, string[]> = {
     apple: state.apple,
     orange: state.orange,
     watermelon: state.watermelon,
     default: ['Not Found'],
  };
  return fruitCategory[fruit] ?? fruitCategory.default;
}

Note that you default “branch” should also return a string[].


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