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

To use the mapkeys function from the lodash library in TypeScript, you will need to install both lodash and its corresponding type definitions package. You can install them using npm by running the following command:

npm install --save lodash @types/lodash
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Once installed, you can import the mapkeys function and use it like this:

index.ts
import { mapKeys } from 'lodash';

interface Person {
  firstName: string;
  lastName: string;
}

const persons: Person[] = [
  {firstName: 'John', lastName: 'Doe'},
  {firstName: 'Jane', lastName: 'Doe'}
];

const keyedPersons = mapKeys(persons, (person) => person.firstName);

console.log(keyedPersons);
// Output: { John: { firstName: 'John', lastName: 'Doe' }, Jane: { firstName: 'Jane', lastName: 'Doe' } }
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In this example, we have defined an interface Person and an array of Person objects. We then use the mapKeys function to transform the array into an object keyed by each person's firstName property. The resulting object is then logged to the console.

Note that we have imported the mapKeys function from the lodash library and used it with the appropriate type definitions. This ensures that TypeScript can correctly verify the types of the function parameters and return value.