Index signatures in typescript

The index signature in TypeScript allows you to define types of properties that are unknown in advance, but can be accessed using strings or numbers. A feature like this is useful when the name of a property of an object is dynamic or unknown.

Here is an example:

interface food {
  [key: string]: string | number;
}

const fruits: food = {
  orange: 2,
  apple: 3,
  banana: "empty",
};

Here another example:

interface ItemPrices {
  [itemName: string]: number;
}

const prices: ItemPrices = {
  apple: 1.0,
  banana: 0.5,
  orange: 0.8,
};

const itemName = "apple";
const priceOfApple = prices[itemName];
console.log(`The price of ${itemName} is $${priceOfApple}`);

When working with objects with varying property sets, index signatures allow you to work with them without explicitly declaring their names.In particular, it comes in handy when dealing with.