Merge array on different key in nodejs

Question

dailyTask=[ { subject: 'Documentation', owner_id: 1 }, { subject: 'SERVICES', owner_id: 2 } ]; emails=[ { employee_id: 1, email_id: '[email protected]' }, { employee_id: 2, email_id: '[email protected]' } ];

merge two arrays on keys owner_id and employee_id and the required result is shown below

output=[ {employee_id:1,owner_id:1,email_id:'[email protected]',subject:'Documentation'}, {employee_id:2,owner_id:2,email_id:'[email protected]',subject:'SERVICES'} ];

I'm not sure of what you're asking, but it has to merge when both id et owner are the same ? It could be quite long on long arrays. — Vollfeiw, Apr 09 '21 at 11:11
https://stackoverflow.com/questions/19480008/javascript-merging-objects-by-id This post should be helpful — David, Apr 09 '21 at 11:11
@David 's linked answer will help, just change the `id:item.id` by `employee_id: item.owner_id`. Keep in mind that this will be slow on big arrays. — Vollfeiw, Apr 09 '21 at 11:16

Nithish · Answer 1 · 2021-04-09T11:24:13.483

You can achieve this using Array.reduce & Object.values

const dailyTasks = [{subject:'Documentation',owner_id:1},{subject:'SERVICES',owner_id:2}];

const emails = [{employee_id:1,email_id:'[email protected]'},{employee_id:2,email_id:'[email protected]'}];

const mergeArrays = (tasks, emails) => {
    return Object.values(tasks.reduce((acc,task) => {
    //fetch the matching email from the list of emails based on employee_id and owner_id
        const matchingEmail = emails.find(({employee_id}) => employee_id === task.owner_id);
        //add/update the object with the task & matching email
        acc[task.owner_id] = {
            ...(acc[task.owner_id] || {}),
            ...task,
            ...matchingEmail
        }
        return acc;
    }, {}));
}

console.log(mergeArrays(dailyTasks, emails));

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Merge array on different key in nodejs

1 Answers1