how to use the flatmapdeep function from lodash in javascript

The flatMapDeep function in lodash can be used to recursively flatten an array of nested arrays, and apply a callback function to each element in the array. Here's an example of how you can use it:

index.tsx
const _ = require('lodash');

// create a nested array of arrays
const array = [1, [2, [3, [4]], 5]];

// use flatMapDeep to flatten the array recursively and double each element
const result = _.flatMapDeep(array, (num) => {
  if (_.isArray(num)) {
    return num.map((n) => n * 2);
  } else {
    return num * 2;
  }
});

console.log(result); // -> [2, 4, 6, 8, 10]
368 chars
16 lines

In the example above, we're using _.flatMapDeep to flatten the array recursively and apply a callback function to each element in the array. The result is a new array with each element doubled.

Note that flatMapDeep is part of the lodash library, so you'll need to install it before you can use it. You can install it via NPM:

index.tsx
npm install lodash
19 chars
2 lines