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

To use the first function from the Underscore library in TypeScript, you'll first need to install the Underscore library and its corresponding TypeScript definitions. You can do this with the following command:

npm install underscore @types/underscore
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Once you've installed the library and its definitions, you can import the first function from the Underscore library and use it in your TypeScript code like so:

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

const numbers = [1, 2, 3, 4, 5];

const firstNumber = _.first(numbers);
console.log(firstNumber); // output: 1
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In the above code, we imported the entire Underscore library using the import * as _ from 'underscore' syntax. We then used the _.first function to extract the first element of the numbers array.

Note that since TypeScript has built-in support for many of the functional programming concepts that Underscore provides, you may find that you need to use Underscore less frequently in TypeScript compared to JavaScript.