Array.prototype and Iterators fun with Dragons.

dragon-array.prototype.js

// Here are some handy Array.prototype methods.
// Also known as higher order functions.

// An Array of Dragon objects for us to work with.
const dragons = [
  { name: 'Fluffykins', color: 'red', size: 'tiny', type: 'fire' },
  { name: 'Puff', color: 'purple', size: 'medium', type: 'time' },
  { name: 'Randy', color: 'green', size: 'small', type: 'nature' },
  { name: 'Smaug', color: 'black', size: 'large', type: 'fire' },
  { name: 'Draco', color: 'green', size: 'medium', type: 'fire' },
  { name: 'Bahamut', color: 'black', size: 'large', type: 'fire' },
  { name: 'Bigsby', color: 'blue', size: 'small', type: 'ice' },
  { name: 'Tiamat', color: 'black', size: 'large', type: 'fire' },
  { name: 'Alduin', color: 'gray', size: 'large', type: 'fire' },
  { name: 'Dracolich', color: 'white', size: 'large', type: 'undead' },
  { name: 'Spyro', color: 'purple', size: 'tiny', type: 'fire' }
]

// Make an Array of Dragon Names
const dragonNames = dragons
  .map(dragon => dragon.name)

// Make an Array of all Large Fire Dragons
const largeFireDragons = dragons
  .filter(dragon => dragon.size === 'large' && dragon.type === 'fire')

// Make an Array of Purple Dragon Names
// Note: We can chain Array.prototype methods together
const purpleDragonNames = dragons
  .filter(dragon => dragon.color === 'purple')
  .map(dragon => dragon.name)

const hasType = type => {
  // Flatten an array to a Boolean (Or any other data type/structure).
  return dragons.reduce((hasType, dragon) => {
    return hasType || dragon.type === type
  }, false)
}

const hasUndead = hasType('undead');

console.log('dragons', JSON.stringify(dragons, null, 2));
console.log('dragonNames', dragonNames);
console.log('largeFireDragons', JSON.stringify(largeFireDragons, null, 2));
console.log('purpleDragonNames', JSON.stringify(purpleDragonNames, null, 2));
console.log('hasUndead', hasUndead);

dragon_iterators.rs

use std::fmt::Debug;

fn main() {
  let dragons = get_dragons();

  let dragon_names: Vec<&str> = dragons
    .iter()
    .map(|d| d.name)
    .collect();
  println!("Dragon Names: {:?}", dragon_names);

  let large_fire_dragons: Vec<_> = dragons
    .iter()
    .filter(|d| d.size == "large" && d.element == "fire")
    .collect();
  println!("Large Fire Dragons: {:?}", large_fire_dragons);

  let purple_dragon_names: Vec<&str> = dragons
    .iter()
    .filter(|d| d.color == "purple")
    .map(|d| d.name)
    .collect();
  println!("Purple Dragon Names: {:?}", purple_dragon_names);

  let has_undead = has_element(&dragons, "undead");
  println!("Has Undead Dragons: {:?}", has_undead);
}

fn has_element(dragons: &Vec<Dragon>, element: &str) -> bool {
  dragons
    .into_iter()
    .any(|d| d.element == element)
}

#[derive(Debug)]
struct Dragon<'a> {
  name: &'a str,
  color: &'a str,
  size: &'a str,
  element: &'a str,
}

fn get_dragons<'dragons>() -> Vec<Dragon<'dragons>> {
  vec![
    Dragon {
      name: "Fluffykins",
      color: "red",
      size: "tiny",
      element: "fire",
    },
    Dragon {
      name: "Puff",
      color: "purple",
      size: "medium",
      element: "time",
    },
    Dragon {
      name: "Randy",
      color: "green",
      size: "small",
      element: "nature",
    },
    Dragon {
      name: "Smaug",
      color: "black",
      size: "large",
      element: "fire",
    },
    Dragon {
      name: "Draco",
      color: "green",
      size: "medium",
      element: "fire",
    },
    Dragon {
      name: "Bahamut",
      color: "black",
      size: "large",
      element: "fire",
    },
    Dragon {
      name: "Bigsby",
      color: "blue",
      size: "small",
      element: "ice",
    },
    Dragon {
      name: "Tiamat",
      color: "black",
      size: "large",
      element: "fire",
    },
    Dragon {
      name: "Alduin",
      color: "gray",
      size: "large",
      element: "fire",
    },
    Dragon {
      name: "Dracolich",
      color: "white",
      size: "large",
      element: "undead",
    },
    Dragon {
      name: "Spyro",
      color: "purple",
      size: "tiny",
      element: "fire",
    },
  ]
}