Outline
- JavaScript Fundamentals -- What is JavaScript?
- JavaScript Fundamentals -- Variables and Scope
- JavaScript Fundamentals -- Primitive Types
- JavaScript Fundamentals -- The this Keyword
-
JavaScript Fundamentals -- The JavaScript Console
- Introduction
- console.log + Exercise
- console.log Exercise Review
- console.info + Exercise
- console.info Exercise Review
- console.warn + Exercise
- console.warn Exercise Review
- console.error + Exercise
- console.error Exercise Review
- console.table + Exercise
- console.table Exercise Review
- console.assert + Exercise
- console.assert Exercise Review
- console.group + Exercise
- console.group Exercise Review
- Conclusion
-
JavaScript Fundamentals -- Logical and Comparison Operators
- Introduction to Logical and Comparison Operators
- Truthy and Falsy Values
- Comparison Operators -- Equality and Inequality
- Comparison Operators -- Equality and Inequality Exercise
- Comparison Operators -- Equality and Inequality Exercise Review
- Comparison Operators -- Relational
- Comparison Operators -- Relational Exercise
- Comparison Operators -- Relational Exercise Review
- Logical Operators -- Or
- Logical Operators -- Or Exercise
- Logical Operators -- Or Exercise Review
- Logical Operators -- And
- Logical Operators -- And Exercise
- Logical Operators -- And Exercise Review
- Logical Operators -- Not
- Logical Operators -- Not Exercise
- Logical Operators -- Not Exercise Review
- Logical Operators -- Nullish Coalescing
- Logical Operators -- Nullish Coalescing Exercise
- Logical Operators -- Nullish Coalescing Exercise Review
- Logical and Comparison Operators Conclusion
-
JavaScript Fundamentals -- Looping in JavaScript
- Introduction to Looping in JavaScript
- for Loops
- for Loops -- Why Use Them and Gotchas
- for ... of Loops
- Looping Exercise 1
- Looping Exercise 1 Review
- for ... in Loops
- Looping Exercise 2
- Looping Exercise 2 Review
- do while Loops
- Breaking out of Loops
- Skipping Passes Through Loops
- Looping Exercise 3
- Looping Exercise 3 Review
- Conclusion to Looping in JavaScript
-
JavaScript Fundamentals -- Functions in JavaScript
- Introduction to Functions in JavaScript
- Named Functions
- Anonymous Functions
- Arrow Functions
- Functions in JavaScript Exercise 1
- Functions in JavaScript Exercise 1 Review
- Default Parameters
- Named Parameters
- Rest Parameters
- Functions in JavaScript Exercise 2
- Functions in JavaScript Exercise 2 Review
- Functions in JavaScript Real Demo
- Conclusion to Functions in JavaScript
- JavaScript Fundamentals -- Strings, Numbers, & Dates
- JavaScript Fundamentals -- Objects in JavaScript
- JavaScript Fundamentals -- Arrays in JavaScript
- JavaScript Fundamentals -- Course Conclusion
Outline
- JavaScript Fundamentals -- What is JavaScript?
- JavaScript Fundamentals -- Variables and Scope
- JavaScript Fundamentals -- Primitive Types
- JavaScript Fundamentals -- The this Keyword
-
JavaScript Fundamentals -- The JavaScript Console
- Introduction
- console.log + Exercise
- console.log Exercise Review
- console.info + Exercise
- console.info Exercise Review
- console.warn + Exercise
- console.warn Exercise Review
- console.error + Exercise
- console.error Exercise Review
- console.table + Exercise
- console.table Exercise Review
- console.assert + Exercise
- console.assert Exercise Review
- console.group + Exercise
- console.group Exercise Review
- Conclusion
-
JavaScript Fundamentals -- Logical and Comparison Operators
- Introduction to Logical and Comparison Operators
- Truthy and Falsy Values
- Comparison Operators -- Equality and Inequality
- Comparison Operators -- Equality and Inequality Exercise
- Comparison Operators -- Equality and Inequality Exercise Review
- Comparison Operators -- Relational
- Comparison Operators -- Relational Exercise
- Comparison Operators -- Relational Exercise Review
- Logical Operators -- Or
- Logical Operators -- Or Exercise
- Logical Operators -- Or Exercise Review
- Logical Operators -- And
- Logical Operators -- And Exercise
- Logical Operators -- And Exercise Review
- Logical Operators -- Not
- Logical Operators -- Not Exercise
- Logical Operators -- Not Exercise Review
- Logical Operators -- Nullish Coalescing
- Logical Operators -- Nullish Coalescing Exercise
- Logical Operators -- Nullish Coalescing Exercise Review
- Logical and Comparison Operators Conclusion
-
JavaScript Fundamentals -- Looping in JavaScript
- Introduction to Looping in JavaScript
- for Loops
- for Loops -- Why Use Them and Gotchas
- for ... of Loops
- Looping Exercise 1
- Looping Exercise 1 Review
- for ... in Loops
- Looping Exercise 2
- Looping Exercise 2 Review
- do while Loops
- Breaking out of Loops
- Skipping Passes Through Loops
- Looping Exercise 3
- Looping Exercise 3 Review
- Conclusion to Looping in JavaScript
-
JavaScript Fundamentals -- Functions in JavaScript
- Introduction to Functions in JavaScript
- Named Functions
- Anonymous Functions
- Arrow Functions
- Functions in JavaScript Exercise 1
- Functions in JavaScript Exercise 1 Review
- Default Parameters
- Named Parameters
- Rest Parameters
- Functions in JavaScript Exercise 2
- Functions in JavaScript Exercise 2 Review
- Functions in JavaScript Real Demo
- Conclusion to Functions in JavaScript
- JavaScript Fundamentals -- Strings, Numbers, & Dates
- JavaScript Fundamentals -- Objects in JavaScript
- JavaScript Fundamentals -- Arrays in JavaScript
- JavaScript Fundamentals -- Course Conclusion
When we declare a function that takes parameters, we generally want the developer (ourselves or someone else) to pass those parameters in. Most of the time, that happens as expected. But sometimes people may forget to pass a parameter in, or maybe you want to allow them to call the function without passing in the parameter and you'll provide a default value. Default parameters for functions is perfect for this use case. Here's how you can provide a default parameter to a function:
function divide(top, bottom = 1) {
return top / bottom;
}
This divide
function expects two parameters, top
and bottom
. The = 1
after the bottom parameter means that if nothing is passed into the function as the bottom parameter, its value will be 1 instead of undefined. So if we call the function like this:
const result = divide(4);
The result will be 4 instead of NaN
, which is a special value in JavaScript that means not a number. Default parameters are easy to implement and can be a way to prevent errors in our code from forgetting to pass all the arguments into a function.
You can learn more about default parameters in this blog post.