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Lodash _.meanBy

Overview

lodash _.meanBy is a powerful method that allows developers to calculate the average of an array of objects by their properties. Specifically, it lets you specify a function that maps each object to a number and uses those numbers to determine the mean.

The syntax for using _.meanBy is straightforward. You pass it two arguments: the first is the array of objects to be averaged, and the second is the mapping function that is used to extract the numerical values from each object. Here is an example of how the method can be used:

const arr = [
  { name: "John", age: 21 },
  { name: "Jane", age: 19 },
  { name: "Alex", age: 25 },
  { name: "Anna", age: 30 },
];

const averageAge = _.meanBy(arr, (person) => person.age);

console.log(averageAge); // 23.75

In this example, we have an array of objects representing people's names and ages. We use _.meanBy to calculate the average age by passing the array and a function that extracts the age property from each object. The result is a number representing the average age of all people in the array.

One of the benefits of using _.meanBy is that it allows for more flexibility when calculating the average of an array of objects. Rather than writing a custom function to iterate over the array and compute the average, _.meanBy handles the heavy lifting by abstracting away the details of the computation. It is especially useful when working with large datasets where performance is a concern.

Additionally, _.meanBy is part of the lodash library, which means it benefits from the library's strong reputation for speed and reliability. The library is well-maintained and has a large community of contributors, so you can be sure that it will work well in many different scenarios.

In conclusion, lodash _.meanBy is a useful method for calculating the average of an array of objects in JavaScript. Developers can use it to extract and compute numerical values across arrays of objects with ease. The method is fast, reliable, and flexible, making it an essential tool in any developer's toolkit.