Face Ctrl

function getData() {
    let textarea=JSON.parse(document.querySelector('textarea').value);
    let peopleInParagraph=document.querySelector('#peopleIn p');
    let peopleOutParagraph=document.querySelector('#peopleOut p');
    let blacklistParagraph=document.querySelector('#blacklist p');
    let lastElement=textarea.pop();

    let peopleIn=[];
    let peopleOut=[];
    let blacklist=[];

    for (const person of textarea) {
        let action=person.action;
        let currentPerson={
            firstName:person.firstName,
            lastName:person.lastName
        }


        if (action==='peopleIn') {
            if (!blacklist.find(p=>p.firstName===currentPerson.firstName &&
                p.lastName===currentPerson.lastName)) {

                    peopleIn.push(currentPerson);
            }
        }else if (action==='peopleOut') {
            if (peopleIn.find(p=>p.firstName===currentPerson.firstName &&
                p.lastName===currentPerson.lastName)) {

                    let index=peopleIn.findIndex(p=>p.firstName===currentPerson.firstName &&
                        p.lastName===currentPerson.lastName);
                    peopleIn.splice(index,1);
                    peopleOut.push(currentPerson);
            }

        }else if (action==='blacklist') {
            if (peopleIn.find(p=>p.firstName===currentPerson.firstName &&
                p.lastName===currentPerson.lastName)) {

                    let index=peopleIn.findIndex(p=>p.firstName===currentPerson.firstName &&
                        p.lastName===currentPerson.lastName);
                    peopleIn.splice(index,1);
                    peopleOut.push(currentPerson);
            }
                blacklist.push(currentPerson);
        }
    }

    let output={};
    output['peopleIn']=peopleIn;

    output['peopleOut']=peopleOut;

    output['blacklist']=blacklist;

    if (lastElement.action!=='' &&
    lastElement.criteria!=='') {
        let criteria=lastElement.criteria;
        output[lastElement.action]=output[lastElement.action]
        .sort((a,b)=>a[criteria].localeCompare(b[criteria]));
    }

    peopleInParagraph.textContent=output.peopleIn
    .map(x=>JSON.stringify(x))
    .join(' ');

    peopleOutParagraph.textContent=output.peopleOut
    .map(x=>JSON.stringify(x))
    .join(' ');

    blacklistParagraph.textContent=output.blacklist
    .map(x=>JSON.stringify(x))
    .join(' ');
}