Testing out batch functionality with dataloader

dataloader.js

const DataLoader = require('dataloader');

const data = [
    {id: 1},
    {id: 2},
    {id: 3},
];

const myLoader = new DataLoader(keys => {
    const results = keys.map(key => data[key - 1]);
    console.log('INVOKED! What are the keys?', keys);
    return Promise.resolve(results);
});

async function execute() {
    const [one, two, four, twoAgain, twoAThirdTime] = await Promise.all([
        myLoader.load(1),
        myLoader.load(2),
        myLoader.load(4),
        myLoader.load(2),
        myLoader.load(2),
    ]);

    console.log([one, two, four, twoAgain, twoAThirdTime]);

    const [oneAgain, three] = await Promise.all([
        myLoader.load(1),
        myLoader.load(3),
    ]);

    console.log([one, two, three, four, oneAgain]);
}

execute();

/**
Output : 

INVOKED! What are the keys? [ 1, 2, 4 ]
[ { id: 1 }, { id: 2 }, undefined, { id: 2 }, { id: 2 } ]
INVOKED! What are the keys? [ 3 ]
[ { id: 1 }, { id: 2 }, { id: 3 }, undefined, { id: 1 } ]

 */