What true and false mean in Javascript. The primary selection and looping constructs.

Arrays are a type of object that are ordered by the index of each item it contains.

Javascript are effectively unordered key/value pairs. The key is formally known as a property and the value can be any valid JavaScript type, even another object.

Functions contain blocks of code that need to be executed repeatedly. Functions can take zero or more arguments, and can optionally return a value.