Morg A side effect is what happens when a function shows a dialog box or writes text on the screen of your computer. By definition, a side effect is something that changes the way a machine works and potentially affects what comes after it. On the other hand, a function can also produce values that don’t … Read more
console.log is a function that writes out its arguments to a device. It’s a special binding expression that takes in the log properties from values held by the console binding. For example, if you were to use console.log in a browser, the output would be on the JavaScript console. You can access the JavaScript console … Read more
When you start up an environment (like turning on a computer or opening up a program), the values you find in that environment have the type function. What is a function? A function is: a portion of a program wrapped in a value performs a single task and you can call that function whenever you … Read more
An environment is a collection of: bindings and their values that exist at any given time. Starting up a program creates an active environment Environments at the start of a program are surprisingly not empty. In fact, these environments start with bindings that are standard to the JavaScript language. Like when you turn on a … Read more
When you’re making binding names, you can make up almost anything. You can even have digits inside a binding name like iamlegend23. However, a few rules you must abide by when coming up with a binding name: The binding name must not start with a digit. The only symbol or special character you can include … Read more
To be honest, the statements let, var, and const can all be used to create bindings. In fact, the binding names created from each statement type can be evaluated together in a single expression. What is let in JavaScript? For now, just understand that let is a statement that initiates the binding of a variable … Read more
To hold onto new values, JavaScript uses something called bindings, or variables. For example: This translates into: Create a binding named holdThisValue and use it to grab a hold of the product of 4 * 5. So you see the keyword let? It means that this statement is going to be a binding. The next … Read more
What is an expression in JavaScript? An expression is a fragment of code that produces a value. For example, you got literal values like 43 or “happy.” These are always expressions! Expressions are also considered something in between parentheses. Binary and unary operators that hold 2 expression values or 1 are also fully considered expressions … Read more
The logical operators (&& and ||) will convert their left-hand value to a Boolean type. It then decides what to return. It can either return the original left-hand value or the right-hand value. The or operator (||) will return the left value if it’s converted to true and it will return the value on the … Read more
Whenever you want to see if a value is actually real instead of just undefined or null, you can use undefined or null to compare it. You can use either the equal to operator (==) and the not equal to operator (!=) for the test. So thanks to JavaScript’s automatic conversions work like this: or … Read more