js4online_homework/08/main.js

// sort
var persons = [
   { name: "Иван", age: 17 },
   { name: "Мария", age: 35 },
   { name: "Алексей", age: 73 },
   { name: "Яков", age: 12 },
]
function personSort(key) {
   persons.sort((a, b) => a[key] > b[key] ? 1 : -1)
}
console.log(sort(persons, "age"));
///////////////////////////////////////////////
console.log(sort(persons, "name", false));
///////////////////////////////////////////////
console.log(sort(persons, "name"));

// array map
var numbers = ["1", {}, null, undefined, "500", 700].map(function (a) { if ((+a) > 0) return +a; else return a })
console.log(numbers)

// array reduce
let number01 = ["0", 5, 3, "string", null];
let number02 = number01.filter(item => typeof item === 'number').reduce((a, b) => a * b)
console.log(number02)

// object filter
var phone = {
   brand: "meizu",
   model: "m2",
   ram: 2,
   color: "black",
};
function filter(object, callback) {
   let filterPhone = {};
   for (let key in object) {
      if (callback(key, object[key])) {
         filterPhone[key] = object[key];
      }
   }
   return filterPhone
}
console.log(filter(phone, (key, value) => key == "color" || value == 2));