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

To use the flatMap function from the lodash library in TypeScript, you first need to install lodash library by running npm install lodash in your project directory.

After installing lodash, you can import the flatMap function in your TypeScript file as shown below:

index.ts
import { flatMap } from 'lodash';

const arr = [[1], [2, 3], [4]];
const flattenedArr = flatMap(arr, (val) => val);

console.log(flattenedArr); // Output: [1, 2, 3, 4]
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In this example, we create an array arr that contains multiple sub-arrays with different lengths. We then use the flatMap function to flatten the array and return a new array with concatenated elements of each sub-array.

The flatMap function takes two arguments: the array to be flattened, and a callback function that is executed on each element of the array. This callback function is used to transform each element of the array into sub-arrays that are concatenated to form a new flattened array.

The flatMap function is a valuable tool in functional programming and enables developers to write more readable and concise code.