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

To use meanby function from the lodash library in TypeScript, we need to first import the function from the lodash library just like we import any other functions in TypeScript.

Here's an example of how to use meanby function in TypeScript:

index.ts
import * as _ from 'lodash';

interface Employee {
  name: string;
  age: number;
  salary: number;
}

const employees: Employee[] = [
  { name: 'John', age: 28, salary: 3000 },
  { name: 'Jane', age: 25, salary: 3500 },
  { name: 'Bob', age: 32, salary: 4000 },
];

const averageSalary = _.meanBy(employees, (employee) => employee.salary);
console.log(averageSalary); // Output: 3500
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In the above example, we first import the entire lodash library using the import * as _ syntax. This allows us to use any functions from the lodash library.

Next, we define an interface Employee that represents the shape of our employee data. We have an array of employee data which we want to find the average salary of.

We then use the _.meanBy() function to calculate the average salary of all employees based on their respective salary property. The _.meanBy() function takes two parameters – an array of objects and a function that returns the numeric value by which the mean will be calculated. We pass a "callback" function as the second parameter which extracts the salary property from each employee object.

Finally, we log the computed average salary to the console.