JSFiddle - React, Tailwind, and code Playground

JavaScript

var allNumbers = [1, 2, 4, 5, 6, 7, '8'],
  someNumbers = [1, 2, 'привет', 4, 5, 6, 7],
  noNumbers = ['это', 'массив', 'без', 'чисел'];

function isNumber(val) {
  return typeof val === 'number';
}

function isAllTrue(source, fileFn) {
  var result;

  for (var i = 0; i < source.length; i++) {

    if (fileFn(source[i]) !== true) {
      return false
    }
  }
  return true;
}
isAllTrue(allNumbers, isNumber)