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

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

// ---------
//  
// ---------
let arr = [1, 2, 3, 4];
arr.every((elem, index, arr) => {
  arr[index + 1]--;
  console.log(`[${arr}][${index}] -> ${elem}`);
  return elem < 2;
});

//  3 ,
//   2  .
//
//   : [1,1,3,4][0] -> 1
//   : [1,1,2,4][1] -> 1
//   : [1,1,2,3][2] -> 2

// ---------
//  
// ---------
arr = [1, 2, 3];
arr.every((elem, index, arr) => {
  arr.push("new");
  console.log(`[${arr}][${index}] -> ${elem}`);
  return elem < 4;
});

//     3 .
//
//   : [1, 2, 3, new][0] -> 1
//   : [1, 2, 3, new, new][1] -> 2
//   : [1, 2, 3, new, new, new][2] -> 3

// ---------
//  
// ---------
arr = [1, 2, 3, 4];
arr.every((elem, index, arr) => {
  arr.pop();
  console.log(`[${arr}][${index}] -> ${elem}`);
  return elem < 4;
});

//   `pop()`  2 .
//
//   : [1,2,3][0] -> 1
//   : [1,2][1] -> 2

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