JSFiddle - React, Tailwind, and code Playground

JavaScript

function checkName(person) {
    console.log('checking name of ' + person.name)
    if (person.name === 'Julie') return true 
}

function checkPersons() {
    var persons = [
        {name: 'Bob', age: 21},
        {name: 'Frank', age: 15},
        {name: 'Julie', age: 12}
    ]
    
    var results = []
    
    persons.forEach(function(person) {
        if (person.age >= 18) {
            console.log('do not need to check name of ' + person.name)
            results.push(person)
        } else {
            setTimeout(function() {
                if (checkName(person)) {
                    console.log('Julie is ' + person.name)
                    results.push(person)
                }
            }, 5000)
        }        
    }) 

console.log(results)
}

checkPersons()