how to use the sum function from the lodash library in typescript

To use the sum() function from the lodash library in TypeScript, you should first install lodash as a dependency of your project. You can do this using the following command:

index.ts
npm install lodash
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Then, to use the sum() function in your TypeScript code, you can import it from the lodash library as follows:

index.ts
import { sum } from 'lodash';
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Finally, you can call the sum() function with an array of numbers as its argument, and it will return the sum of those numbers:

index.ts
const numbers = [1, 2, 3, 4, 5];
const total = sum(numbers); // Returns 15
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You can also use the sum() function with an array of objects by providing a callback function that returns the value to be summed for each object. For example:

index.ts
interface Product {
  name: string;
  price: number;
}

const products: Product[] = [
  { name: 'widget', price: 10 },
  { name: 'gizmo', price: 5 },
  { name: 'thingamabob', price: 20 },
];

const totalPrice = sum(products, (product) => product.price); // Returns 35
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In this example, the sum() function takes an array of Product objects and a callback function that returns the price property of each object. The function then calculates the sum of those values and returns the result.