JS Activity: Find an object in an array

README.md

JS Activity: Finding an object in an array

When an array contains objects, you can use a higher order array method, such as Array.find(), to find an object that matches a particular property value.

Key Takeaways

• Array.find() loops through an array of objects and expects a Boolean return value:
  • If true is returned, the loops stops and Array.find() returns the current item;
  • If false is returned, the loop continues to the next item;
  • If no items are found by the end of the loop, Array.find() returns undefined.
• This method is considered a higher order function, meaning it hides (abstracts) information so we can tackle a problem at a higher (more abstract level). In this case, Array.find() hides the fact that it's looping through the array (and that it operations differently based on a boolean result).

Instructions

1. Download or fork/clone this Gist into your workspace.
2. Using conditional statements and the Array.includes() method, test if the entered command line value exists in the characterClasses array:

   • If true log the following to the console:

     "[inputted value]" is a valid Character Class!`
     

   • If false log the following to the console:

     "[inputted value]" is NOT a valid Character Class! Please try again.`
     

Stretch Activity

Try validating the user input before testing: - inputValue value missing: "Please enter a Character Class";

Spoilers

A potential answer to this activity.

app.js

// Accept command line input
const inputValue = process.argv[2];

// Define data array
const guild = [
  // Item 1
  {
    // general
    id: 1,
    name: 'Harry',
    class: 'wizard',
    race: 'elf',
    // stats
    strength: 16,
    dexterity: 14,
    constitution: 12,
    intelligence: 14,
    wisdom: 16,
    charisma: 10,
    // Modifiers
    poisoned: false
  },
  // Item 2
  {
    // general
    id: 2,
    name: 'Ryan Reynolds',
    class: 'bard',
    race: 'human',
    // stats
    strength: 12,
    dexterity: 16,
    constitution: 14,
    intelligence: 6,
    wisdom: 10,
    charisma: 20,
    // Modifiers
    poisoned: true
  },
  {
    // general
    id: 3,
    name: 'Spry',
    class: 'rogue',
    race: 'elf',
    // stats
    strength: 6,
    dexterity: 18,
    constitution: 10,
    intelligence: 18,
    wisdom: 14,
    charisma: 8,
    // Modifiers
    poisoned: false
  }
];

// Your code here


// Log the results
if (matchingCharacter) {
  console.log(`Found a guild member with a class of ${inputValue}: \n${matchingCharacter}`);
} else {
  console.log(`Couldn't find any guild members with a class of ${inputValue}. Please try again.`);
}