filter-intro.js

const dogs = [
  {name: 'Snookums', needsShots: true, breed: 'pug', age: 2},
  {name: 'Thor', needsShots: true, breed: 'hound', age: 1},
  {name: 'Wunderbar', needsShots: false, breed: 'pug', age: 9},
]

// Lets see how a filter method might work... 

const dogsToSeeVet = dogs.myFilter(function(dog) {
  
  // Does the dog need a shot?
  if(dog.needsShots === true) {
    
    // Lets line them up with the doctor
    return true
  }
  else {
    
    // No need for this dog to see the vet
    return false  
  }
})

// Of course that works! But we can stream line this a bit 
const dogsToSeeVet2 = dogs.myFilter(dog => {
  
  // return the value at the needsShots key which is either true or false
  return dog.needsShots
})

// And for those flying fast these days, ES6 with an implied return
const dogsToSeeVet3 = dogs.myFilter(dog => dog.needsShots)

console.log(dogsToSeeVet)  // Looks like Snookums and Thor
console.log(dogsToSeeVet2) // have a date with the Vet
console.log(dogsToSeeVet3) // to get their shots!