how to use the collect function from the underscore library in typescript

The collect function from the Underscore library is used to transform elements of an array using a provided iterator function. Here's an example in Typescript:

index.ts
import * as _ from "underscore";

interface Item {
  name: string;
  price: number;
}

const items: Item[] = [
  { name: "apple", price: 0.5 },
  { name: "banana", price: 0.25 },
  { name: "orange", price: 0.75 }
];

const itemNames: string[] = _.collect(items, item => item.name);

console.log(itemNames); // Output: ["apple", "banana", "orange"]
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In the example above, we import the Underscore library using the * as _ syntax. We define an interface for the items in our array, and then create an array of Item objects.

The _.collect function takes two parameters: the array to be transformed, and an iterator function. The iterator function takes an item from the array as its parameter and returns the transformed value. In this case, we're transforming each Item object into its name property.

The transformed values are then returned as a new array by the _.collect function and assigned to the itemNames variable. Finally, we log the itemNames array to the console.

Overall, the collect function is a powerful tool for transforming an array in a functional and concise way.