eFarmony Data Structures: Arrays as Collections

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In this section we will review arrays and learn how to create a collection of animal objects.

You will be placing all your code into the scripts.js file.

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Create an array:

• Create a variable called noiseArray and assign it to an array literal. Place at least one element in the array.

Using a native array method…

• Add a noise to the beginning of the noiseArray.
• Add another noise to the end of the noiseArray.

Using Bracket Notation…

• Add another noise to the end.

Inspect the noiseArray:

• What is the length?
• What is the last index? How is it different than the length?
• Inspect your handiwork! What does it look like?

Nest the array in the object:

• Put the noiseArray inside the animal object on the noises property. Your result should look like this:

  { username: 'DaffyDuck', tagline: 'Yippeee!', noises: ['quack', 'honk', 'sneeze'] }

• Congrats! You just made a nested data structure :)

Review

Let's go over some concepts:

• What are the different ways you can add properties and values to arrays?
• Come up with two ways you can add an element to the end of an array, without knowing the exact length of the array.

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Animal Collection

A collection is an array of objects.

• Create a variable called animals and set it equal to an empty array.
  • Note that this variable is animals (plural) while the variable in the Animal User Model of the Object Exercises is animal (singular).
• Using any method you prefer, add your animal from the Object Exercises to the animals array.
• Create a variable called quackers and assign it to this example object:
  • { username: 'DaffyDuck', tagline: 'Yippeee!', noises: ['quack', 'honk', 'sneeze', 'growl'] }
• Add quackers to the animals array using a different method than before.
• Inspect your animals array to ensure you have two objects inside.
• Create two more animal objects and add them to your animals array. They should have these properties and your choice of values:
  • username (with a string value)
  • tagline (with a string value)
  • noises (with an array of values)
• Check the length property of your array. It should give you 4.