Array.prototype.filter()

const words = ["spray", "elite", "exuberant", "destruction", "present"];

const result = words.filter((word) => word.length > 6);

console.log(result);
// : Array ["exuberant", "destruction", "present"]

filter(callbackFn)
filter(callbackFn, thisArg)

function isBigEnough(value) {
  return value >= 10;
}

const filtered = [12, 5, 8, 130, 44].filter(isBigEnough);
// filtered is [12, 130, 44]

const array = [-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13];

function isPrime(n) {
  if (n < 2) {
    return false;
  }
  if (n % 2 === 0) {
    return n === 2;
  }
  for (let factor = 3; factor * factor <= n; factor += 2) {
    if (n % factor === 0) {
      return false;
    }
  }
  return true;
}

console.log(array.filter(isPrime)); // [2, 3, 5, 7, 11, 13]

const arr = [
  { id: 15 },
  { id: -1 },
  { id: 0 },
  { id: 3 },
  { id: 12.2 },
  {},
  { id: null },
  { id: NaN },
  { id: "undefined" },
];

let invalidEntries = 0;

function filterByID(item) {
  if (Number.isFinite(item.id) && item.id !== 0) {
    return true;
  }
  invalidEntries++;
  return false;
}

const arrByID = arr.filter(filterByID);

console.log("\n", arrByID);
// 
// [{ id: 15 }, { id: -1 }, { id: 3 }, { id: 12.2 }]

console.log(" =", invalidEntries);
//  = 5

const fruits = ["apple", "banana", "grapes", "mango", "orange"];

/**
 * 
 */
function filterItems(arr, query) {
  return arr.filter((el) => el.toLowerCase().includes(query.toLowerCase()));
}

console.log(filterItems(fruits, "ap")); // ['apple', 'grapes']
console.log(filterItems(fruits, "an")); // ['banana', 'mango', 'orange']

const names = ["JC63", "Bob132", "Ursula89", "Ben96"];
const greatIDs = names
  .map((name) => parseInt(name.match(/\d+/)[0], 10))
  .filter((id, idx, arr) => {
    // arr 
    // 
    if (idx > 0 && id <= arr[idx - 1]) return false;
    if (idx < arr.length - 1 && id <= arr[idx + 1]) return false;
    return true;
  });
console.log(greatIDs); // [132, 96]

console.log([1, , undefined].filter((x) => x === undefined)); // [undefined]
console.log([1, , undefined].filter((x) => x !== 2)); // [1, undefined]

const arrayLike = {
  length: 3,
  0: "a",
  1: "b",
  2: "c",
  3: "a", // length  3  filter() 
};
console.log(Array.prototype.filter.call(arrayLike, (x) => x <= "b"));
// [ 'a', 'b' ]