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Lodash _.unzipWith

Overview

The lodash _.unzipWith method is a utility function that works similar to JavaScript's built-in zip method. The difference is, zip merges multiple arrays into one by combining the corresponding elements from each array, and unzipWith does the opposite by taking an array of arrays and returning a new array of arrays, where each array contains all the elements at a given index from the original nested arrays.

Moreover, _.unzipWith also accepts an optional iteratee function that is applied to each group of elements before it is combined into a new array. The iteratee function can be used to customize how the elements are combined.

Here's an example of using _.unzipWith:

const lodash = require('lodash');

const zipped = lodash.zip(['a', 'b'], [1, 2], [true, false]);

// Output: [['a', 1, true], ['b', 2, false]]
console.log(lodash.unzipWith(zipped));

// Output: [3, -3]
console.log(lodash.unzipWith(zipped, (arr) => lodash.sum(arr)));

In the example above, zip was used to combine three separate arrays into a single nested array. Then, unzipWith was called to separate the nested array back into separate arrays. The optional iteratee function was also passed, which took each group of elements and summed them using lodash's sum function.

In general, _.unzipWith can be useful when working with data sets that are represented as nested arrays, and you need to extract or manipulate the values at a certain index across all the nested arrays.