Array.prototype.every()

const isBelowThreshold = (currentValue) => currentValue < 40;

const array1 = [1, 30, 39, 29, 10, 13];

console.log(array1.every(isBelowThreshold));
// : true

every(callbackFn)
every(callbackFn, thisArg)

function isBigEnough(element, index, array) {
  return element >= 10;
}
[12, 5, 8, 130, 44].every(isBigEnough); // false
[12, 54, 18, 130, 44].every(isBigEnough); // true

const isSubset = (array1, array2) =>
  array2.every((element) => array1.includes(element));

console.log(isSubset([1, 2, 3, 4, 5, 6, 7], [5, 7, 6])); // true
console.log(isSubset([1, 2, 3, 4, 5, 6, 7], [5, 8, 7])); // false

const numbers = [-2, 4, -8, 16, -32];
const isIncreasing = numbers
  .filter((num) => num > 0)
  .every((num, idx, arr) => {
    // arr 
    // 
    if (idx === 0) return true;
    return num > arr[idx - 1];
  });
console.log(isIncreasing); // true

console.log([1, , 3].every((x) => x !== undefined)); // true
console.log([2, , 2].every((x) => x === 2)); // true

const arrayLike = {
  length: 3,
  0: "a",
  1: "b",
  2: "c",
  3: 345, // length  3  every() 
};
console.log(
  Array.prototype.every.call(arrayLike, (x) => typeof x === "string"),
); // true