Convert an array of objects to a single object

JavaScript version

const toObject = (arr, key) => arr.reduce((a, b) => ({ ...a, [b[key]]: b }), {});

// Or
const toObject = (arr, key) => Object.fromEntries(arr.map((it) => [it[key], it]));

TypeScript version

const toObject = <T extends Record<string, any>, K extends keyof T>(arr: T[], key: K): Record<string, T> => (
    arr.reduce((a, b) => ({ ...a, [b[key]]: b }), {})
);

const toObject = <T extends Record<string, any>, K extends keyof T>(arr: T[], key: K): Record<string, T> => (
    Object.fromEntries(arr.map((it) => [it[key], it]))
);

Example

toObject(
    [
        { id: '1', name: 'Alpha', gender: 'Male' },
        { id: '2', name: 'Bravo', gender: 'Male' },
        { id: '3', name: 'Charlie', gender: 'Female' },
    ],
    'id'
);
/* 
{
    '1': { id: '1', name: 'Alpha', gender: 'Male' },
    '2': { id: '2', name: 'Bravo', gender: 'Male' },
    '3': { id: '3', name: 'Charlie', gender: 'Female' },
}
*/