Introduction to Objects

A key is like a variable name that points to a location in memory that holds a value. A key’s value can be of any data type in the language including functions or other objects.

We separate each key-value pair in an object literal with a comma (,). Keys are strings, but when we have a key that does not have any special characters in it, JavaScript allows us to omit the quotation marks.

dot notation, .

EX: 1. Create a variable crewCount and assign the spaceship‘s numCrew property to it.

2. Create a variable planetArray and assign the spaceship‘s flightPath property to it.

using bracket notation, [ ]

Note: We *must* use bracket notation when accessing keys that have numbers, spaces, or special characters in them. Without bracket notation in these situations, our code would throw an error.

EX: Using bracket notation and also how to log the variable from the notation above.

the assignment operator, =

You can delete a property from an object with the delete operator.

Notes : When the data stored on an object is a function we call that a method.

Objects are passed by reference. This means when we pass a variable assigned to an object into a function as an argument, the computer interprets the parameter name as pointing to the space in memory holding that object.

EX: Write a function greenEnergy() that has an object as a parameter and sets that object’s 'Fuel Type' property to 'avocado oil'.