iterators-every.js

// Iterators .every() Method

// The every() method tests whether all elements in the array pass the test
// implemented by the provided function. It returns a Boolean value.

const words = ['unique', 'uncanny', 'pique', 'oxymoron', 'guise'];

words.every(word => {
  return word.length > 5;
}); // => false

function sourcePlant (food) {
  if(food.source === 'plant') {
    return true;
  }
  return false;
};

const isTheDinnerVegan = arr => {
  if(arr.every(sourcePlant)) {
    return true;
  } else {
    return false;
  }
};

const dinner = [
  {name: 'hamburger', source: 'meat'},
  {name: 'cheese', source: 'dairy'},
  {name: 'ketchup', source:'plant'},
  {name: 'bun', source: 'plant'},
  {name: 'dessert twinkies', source:'unknown'}
];

const veganDinner = [
  {name: 'hamburger', source: 'plant'},
  {name: 'cheese', source: 'plant'},
  {name: 'ketchup', source:'plant'},
  {name: 'bun', source: 'plant'},
  {name: 'dessert twinkies', source:'plant'}
];

isTheDinnerVegan(dinner) // => false
isTheDinnerVegan(veganDinner) // => true