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Lodash _.fromPairs

Overview

The lodash _.fromPairs method is a powerful utility function that allows developers to create a new object from an array of key-value pairs. Using _.fromPairs, developers can easily transform data from one format to another, making it an essential tool for data processing and manipulation.

To use _.fromPairs, developers simply need to pass an array of key-value pairs as an argument. The method then returns a new object with keys and values extracted from the input array. The keys are extracted from the first element of each subarray, and the values are extracted from the second element. For example:

const pairs = [['a', 1], ['b', 2], ['c', 3]];
const obj = _.fromPairs(pairs);
console.log(obj); // { a: 1, b: 2, c: 3 }

While this may seem like a trivial operation, _.fromPairs is particularly helpful when working with data that is formatted as an array of key-value pairs. By transforming the data into an object, developers can more easily access and manipulate the data, particularly when working with complex data structures.

Additionally, _.fromPairs can be used in combination with other lodash methods, such as _.map, _.filter, and _.reduce, to perform complex data manipulations. For example, it could be used to transform an array of objects into an object of objects, with a unique ID as the key:

const data = [
  { id: 1, name: 'Alice', age: 32 },
  { id: 2, name: 'Bob', age: 28 },
  { id: 3, name: 'Charlie', age: 21 },
];

const obj = _.fromPairs(_.map(data, d => [d.id, d]));
console.log(obj);
/*
{
  1: { id: 1, name: 'Alice', age: 32 },
  2: { id: 2, name: 'Bob', age: 28 },
  3: { id: 3, name: 'Charlie', age: 21 }
}
*/

In this example, _.map is used to transform the input array into an array of key-value pairs, where the key is the object ID and the value is the object itself. _.fromPairs is then used to transform this array into an object.

Overall, _.fromPairs is a powerful utility function that simplifies data processing by transforming arrays of key-value pairs into objects. Its simplicity makes it easy to use, while its flexibility makes it an essential tool for data manipulation.